[QUESTION mp2]creating own handler for mod_perl

Hi,

for my diploma thesis I need to implement some of the WebDAV requests
into my apache, to make a TWiki installation (an open-source wiki)
WebDAV compatible.
I know that there is a WebDAV module for the apache but when looking
at the needed connection between the Apache and TWiki, writing a
custom module/handler for mod_perl (a bit like the CPAN module
Apache::WebDAV) than to change the mod_dav code seems to be easier
(and better to maintain).

I am quite experienced programming with perl but I have never done
anything with mod_perl before. After reading in your documentation and
testing some example handlers I still don't really know how to start
and there are also some open questions:

 - I do not understand the link between API and APR functions/methods
(I am working on a Debian Server and really don't care for Windows)

 - in Apache::RequestIO there is the read function but it says that's
for reading from client side. Does that mean reading an input stream
given by the client?

 - when can I use normal perl code and when do I have to use one of
the provided functions/methods? Is it normal perl code for everything
happening on the server (like reading from a file on the server) and
mod_perl functions for everything that happens between server and
client?

Would it be useful to get the mod_perl2 book from Stas Bekman (or
other books), or does it handle more of the general "install and setup
mod_perl" - themes than writing own handlers?

Thanks a lot for help and tips!
Carla