ipb, wordpress and xaraya

Hi,
I post here because i need some clues about login and this hack is not
directly link to xaraya.
On my site i use the authinvision module, who works very well.
Now i want to add wordpress (http://wordpress.org/) who seems to be a good
blog.
I don't want my members to subscribe an other time then i want to use the
ipb users table.
The wordpress blog has a login file.
If i add some rows into the ipb tables (if wordpress need them) and i change
the login wordpress file to check this ipb table (instead of the wordpress
users table) can i except this to work?
Or will i have some problems with sessions or anything else i can't manage
with my poor php knowledge level?
I don't want to sync the wordpress users table with ipb users table, members
have to register only with ipb (for xaraya also).
thanx
chris
ps : i know i would use the blog system from xaraya but i want to offer to
ALL my members a personnal blog, i'm not sure i can do this with xaraya.