Odd date output from biblatex-apa

Question

I am using biblatex-apa for my references and I have this enty in my .bib file:

@ONLINE{habitat,
    TITLE = {Mission, Vision \& Values},
    URL = {http://www.tchabitat.org/missionvisionvalues},
    ORGANIZATION = {Twin Cities Habitat for Humanity website},
    URLDATE = {2011-09-15}
}

The output shows the date of the reference as 'Retrieved 15 September 2011 from...'. Shouldn't the date be like the english date format, September 15th, 2011?

EDIT:

This is my preamble

\documentclass[letterpaper]{apa6e}
\usepackage{url}
\usepackage[margin=1in]{geometry}
\usepackage[american]{babel}
\usepackage{csquotes}
\usepackage[style=apa]{biblatex}
\DeclareLanguageMapping{american}{american-apa}
\bibliography{libros}
\defbibheading{bibliography}{\section*{\normalfont\refname}}

Answer 1

I've just uploaded version 3.6 to CTAN which should fix this. Thanks for spotting it. I realised that the APA 6th edition manual which I used to write the style has not one example of "Retrieved on" in chapter 7. So, it slipped by me. APA 5th edition had many. Strange really since the 6th edition is so focussed on "new media" formats ...

Answer 2

To obtain an APA-compliant date (to my understanding) I modified the american-apa.lbx file. I changed the function \mkbibdateapalongdmy to read as follows

\protected\def\mkbibdateapalongdmy#1#2#3{%
 \iffieldundef{#2}
   {}
   {\mkbibmonth{\thefield{#2}}}
 \iffieldundef{#3}
   {}
   {\stripzeros{\thefield{#3}}}
 \iffieldundef{#1}
   {}
   {\ifthenelse{\iffieldundef{#2}\OR\iffieldundef{#3}}
     {}
     {\addcomma\addspace}
     \thefield{#1}
   }
 }

This produces the output date 'September 15, 2011'.

Disclaimer: I succeeded in getting the output I wanted, but I cannot guarantee that this won't break something else. As far as I understand from reading the code, the \mkbibdateapalongdmy function is called for entries of type url and event but it might be used in other cases.