I just had to start bgII again and this time i decided to go solo and try out the infamous kensai 13/mage combo. Just a few hours ago i finaly dinged 14 with a mage (and what a pain it was) and realised i still have human warrior avatar, which i promptly fixed with SK. The bigger problem was that the inventory screen remained the same as that of a mage, which means i only have 2 main hand weapon spaces.
It's not that big of a deal, but i like to switch weapons around depending on enemies i fight, or to use weapon's special abilities and with only two slots, this is severely hampered.
I've fiddled with SK a bit, but havent been able to find anything that'd help restore warrior's 4 main hand slots.

Anyone knows the trick?

I think it's hardcoded, so there's no way around it. I'm not a 100% sure though.