report/book: how to customize \part look (the page itself and listing in ToC)?

Question

I was wondering how I can 'split' up a latex document into 'volumes'. The final TOC should read something like this:

Volume 1                                     2
1. chapter 1 of volume 1                     3 
2. chapter 2 of volume 2                    15    

Volume 2                                    35
1. chapter 1 of volume 2                    36
2. chapter 2 of volume 2                    40

the following code gives me the correct chapter numbering, but unfortunately the parts get numbered too

\documentclass[openright]{scrreprt}

% enforces that chapter numbering restarts after each 'part'
\makeatletter\@addtoreset{chapter}{part}\makeatother%

\usepackage{lipsum}% for dummy text

\begin{document}

\tableofcontents 

\part{Volume 1}
\chapter{chapter 1 of volume 1}
\lipsum[1-10]
\chapter{chapter 2 of volume 1}
\lipsum[1-10]

% volume 2 starts with its own chapter numbering
\part{Volume 2}
\chapter{chapter 1 of volume 2}
\lipsum[1-10]
\chapter{chapter 2 of volume 2}
\lipsum[1-10]

\end{document}

this is the result:

I. Volume 1                                  2
1. chapter 1 of volume 1                     3 
2. chapter 2 of volume 2                    15    

II. Volume 2                                35
1. chapter 1 of volume 2                    36
2. chapter 2 of volume 2                    40

Questions:

1. How do I get rid of the 'I.' and 'II.' in the TOC?
2. Each part page now reads "part I. Volume 1" - how can I get rid of the "part I"?
3. is there a way to customize the look of the part page? For each part I would like to put a few lines of text below

EDIT:

Quick and dirty solution to question #1:

\documentclass[openright]{scrreprt}

% enforces that chapter numbering restarts after each 'part'
\makeatletter\@addtoreset{chapter}{part}\makeatother%
\renewcommand\partname{Volume}
\usepackage{lipsum}% for dummy text

% show chapter & section in TOC, no subsection
\setcounter{tocdepth}{1}

\begin{document}

\tableofcontents 

% don't add Volume 1 to TOC
\part*{this is volume 1}
% add manual entry for volume 1
\addcontentsline{toc}{part}{this is volume 1}
\chapter{chapter 1 of volume 1}
\lipsum[1-10]
\section{sdfg}

\end{document}

Answer 1

Either get rid of the number replacing \part by \addpart:

\documentclass[openright]{scrreprt}

\usepackage{lipsum}% for dummy text

\begin{document}

\tableofcontents 

\addpart{Volume 1}\setcounter{chapter}{0}
\chapter{chapter 1 of volume 1}
\lipsum[1-10]
\chapter{chapter 2 of volume 1}
\lipsum[1-10]

% volume 2 starts with its own chapter numbering
\addpart{Volume 2}\setcounter{chapter}{0}
\chapter{chapter 1 of volume 2}
\lipsum[1-10]
\chapter{chapter 2 of volume 2}
\lipsum[1-10]

\end{document}

You have to reset the chapter counter in this case, because the part counter would not be increased.

Or you may replace part by volume:

\documentclass[openright]{scrreprt}

% enforces that chapter numbering restarts after each 'part'
\makeatletter\@addtoreset{chapter}{part}\makeatother%
\renewcommand*{\thepart}{\arabic{part}}
\renewcommand*{\partname}{Volume}

\usepackage{lipsum}% for dummy text

\begin{document}

\tableofcontents 

\part[Volume]{}
\chapter{chapter 1 of volume 1}
\lipsum[1-10]
\chapter{chapter 2 of volume 1}
\lipsum[1-10]

% volume 2 starts with its own chapter numbering
\part[Volume]{}
\chapter{chapter 1 of volume 2}
\lipsum[1-10]
\chapter{chapter 2 of volume 2}
\lipsum[1-10]

\end{document}

But in this case you will have 1 Volume instead of Volume 1 at the table of contents.

I would use a modified 1st solution:

\documentclass[openright]{scrreprt}

\usepackage{lipsum}% for dummy text

\newcommand*{\volume}[1][]{% optional argument: additional text
  \cleardoublepage\refstepcounter{part}%
  \setpartpreamble{#1}% add this preamble below the heading
  \addpart{Volume \thepart}
}
\renewcommand*{\thepart}{\arabic{part}}
% enforces that chapter numbering restarts after each 'part'
\makeatletter\@addtoreset{chapter}{part}\makeatother%


\begin{document}

\tableofcontents 

\volume[{\begin{abstract}\lipsum[1]\end{abstract}}]% Volume with additional text below heading.
\chapter{chapter 1 of volume 1}
\lipsum[1-10]
\chapter{chapter 2 of volume 1}
\lipsum[1-10]

\volume
\chapter{chapter 1 of volume 2}
\lipsum[1-10]
\chapter{chapter 2 of volume 2}
\lipsum[1-10]

\end{document}

To add some text below the part head \setpartpreamble{…} has been used. See the KOMA-Script manual (page 91f at the current version of scrguien.pdf) for more information.