If you want to be able to use V4, then click on 'Source File' browse to the V4 Cr2 (ie:program filesefrontierruntimelibrariescharacterdaz peoplevictoria 4.cr2) then click create new, fill in the spaces in the little window that pops up, click ok, then click on the v4.cr2 again in the next window, another window pops up, just click continue, scroll down your link library and your new 'definition file' should be there ;)  You would do the same for any 'model' you wanted to use in IPB. Hope that helps and I didn't confuse you none.
Jen