Adding a new EE_CHAR_* attrib id

Hi all,
I am trying to add a new text attribute in EditEng (background color) and I
had a couple questions on the process:

*Premise*:
I already modified some obvious places:
- i added classes SvxBackgroundColorItem and EditCharAttribBackgroundColor
- i defined EE_CHAR_BKGCOLOR and included its use in several
switch...case-s where other EE_CHAR_* tags are dealt with.

1) I'm asking help to understand where these attributes are "created" after
the document model is modified, for example:
 - which methods are called to create a Color attribute after fo:color is
read in a document?
 - which methods are called to create a Color attribute after the user sets
a particular font color?

2) SfxItemPool and SfxPoolItem seem important classes for the purposes
above. I stumbled upon the method SfxItemPool::SetVersionMap used in
editdoc.cxx to set some "version maps". From some of the comments in that
file I suspect that these maps may have to be modified to include the new
EE_CHAR_* I created. But no clue on that.
Does anyone know what the method SetVersionMap actually does and whether i
should modify the version maps set in the constructor of EditEngineItemPool?

Cheers,
Matteo