How do I write “This page intentionally left blank.” in memoir with custom chapter styles?

Question

Solved by inserting this in the preamble (made by touhami from the comments):

\makeatletter \def\clearforchapter{\clearpage\if@twoside \ifodd\c@page\else \hbox{}\vfill\begin{center}This page intentionally left blank.\end{center}\vfill \thispagestyle{cleared}%
\newpage\if@twocolumn\hbox{}\newpage\fi\fi\fi}\makeatother

This puts the line in the middle of the blank page.

---

Who do I write “This page intentionally left blank.” on left (even numbered) blank pages? I've searched and found many solutions, which doesn't work with my setup. My custom made chapters start on a right (odd numbered) side. Solutions that I've found, but didn't work for me:
How do I make pages which were "intentionally left blank"?
How to make "This page intentionally left blank." in KOMA script
"This page was left intionally blank" on center of page
https://gist.github.com/philipptempel/5220000

My setup is like this (If you were wondering, my notes are in Danish):

Preamble:

\documentclass[a4paper,11pt,oldfontcommands]{memoir}
\setlrmarginsandblock{2.5cm}{1.5cm}{1} 
\setulmarginsandblock{2.5cm}{*}{1} 
\setheadfoot{2\onelineskip}{\footskip}
\checkandfixthelayout
\usepackage{tikz}
\usepackage{lipsum}
\usetikzlibrary{positioning}

%%%%%%
% CHAPTER STYLES
%%%%%%
\makechapterstyle{simple}{
  \renewcommand*{\printchaptername}{}
  \setlength{\afterchapskip}{1cm}       
  \renewcommand*{\printchaptertitle}[1]{\flushleft\chaptitlefont##1}
  }

\makechapterstyle{box}{%
  \setlength{\midchapskip}{-58pt}       %
  \setlength{\afterchapskip}{10mm}      %
  \renewcommand*{\printchaptername}{}   %
  \renewcommand*{\printchapternum}{     %
    \flushleft
    \begin{tikzpicture}
      \draw [fill=black] (0,0) rectangle (2cm,2cm);
      \node [text=white] at (1cm,1cm) { \chapnumfont\thechapter };
    \end{tikzpicture}}%
  \renewcommand{\printchaptertitle}[1]{%
        \hspace*{30mm}\chaptitlefont\MakeUppercase{##1}}} 

\makeatletter
\settocpreprocessor{chapter}{%
  \let\tempf@rtoc\f@rtoc%
  \def\f@rtoc{%
  \texorpdfstring{\MakeTextUppercase{\tempf@rtoc}}{\tempf@rtoc}}%
}
\makeatother

%%%%%%
% gør at subsections også nummeres
%%%%%%
\setsecnumdepth{subsection}
\usepackage{graphicx}
\usepackage{framed}
\usepackage[danish]{babel}

%%%%%%
% PAGESTYLE
%%%%%%
\copypagestyle{chapter}{plain} %Dette kopierer "plain"-stilen, så den kan overskrives, og sætte sidetal på højre/venstre side ved kapitelstart.
\makeoddfoot{chapter}
  {}% Venstre side.
  {}% Midten.
  {\thepage}% Højre side.
\makeevenfoot{chapter}
  {\thepage}% Venstre side.
  {}% Midten.
  {}% Højre side.

\makepagestyle{bachelor}
\makepsmarks{bachelor}{
  \createmark{chapter}      {both}{shownumber}{}{. \ }
  \createmark{section}      {both}{shownumber}{}{ -\ } 
}
\makeoddhead{bachelor}%
  {}%
  {}%
  {\rightmark}%
\makeevenhead{bachelor}%
  {\leftmark}%
  {}%
  {}
% sidens fod: sidetal/sidste side
\makeoddfoot{bachelor}
  {} %venstre side.
  {} %midten.
  {\thepage} %højre side.
\makeevenfoot{bachelor}
  {\thepage} %venstre side.
  {} %midten.
  {} %højre side.
% smid en linje under
\makeheadrule{bachelor}{\textwidth}{\normalrulethickness}

%%%% Laver pagestyle til appendiks
\makepagestyle{appendiks}
\makepsmarks{appendiks}{
  \createmark{chapter}      {both}{shownumber}{}{ -\ }
}
\makeoddhead{appendiks}%
  {}%
  {}%
  {\rightmark}%
\makeevenhead{appendiks}%
  {\leftmark}%
  {}%
  {}
\makeoddfoot{appendiks}
  {} %venstre side.
  {} %midten.
  {\thepage} %højre side.
\makeevenfoot{appendiks}
  {\thepage} %venstre side.
  {} %midten.
  {} %højre side.
\makeheadrule{appendiks}{\textwidth}{\normalrulethickness}

\nouppercaseheads
\pagestyle{bachelor}
%%%%%%

Content:

\begin{document}
\chapterstyle{simple}

\chapter*{Chapter guide}
Gives an overview and acts as a guide for the report.
\tableofcontents* 
\chapterstyle{box} 
\pagestyle{bachelor}

\chapter{First Chapter}
\lipsum

\chapterstyle{simple} 
\bibliography{sources} 
\chapterstyle{box}
\pagestyle{appendiks}

\appendix
\input{appendix.tex} 
\end{document}

Any help is greatly appreciated.

Answer 1

Solved by inserting this in the preamble (made by touhami from the comments):

\makeatletter \def\clearforchapter{\clearpage\if@twoside \ifodd\c@page\else \hbox{}\vfill\begin{center}This page intentionally left blank.\end{center}\vfill \thispagestyle{cleared}%
\newpage\if@twocolumn\hbox{}\newpage\fi\fi\fi}\makeatother

This puts the line in the middle of the blank page.

Answer 2

Section 18.13 of the memoir manual (texdoc memman or texdoc memoir) deals with issues like this. For instance:

\chapter{One}
...
\cleartooddpage[\vspace*{\fill}\centering BLANK PAGE \vspace*{\fill}]
\chapter{Next}

will center BLANK PAGE both vertically and horizontally if the page before \chapter{Next} would be even numbered.