I thought OWA uses tcp port 80 by default, or 443 if you use https. Ignore the rest if this fact is wrong. Otherwise ...
In your config there is nothing to allow the www traffic in the access-list outside_access_in
access-list outside_access_in extended permit tcp any interface outside eq 80
and no static nat for this
static (inside,outside) tcp interface 80 192.168.0.254 80 netmask 255.255.255.255
I think these must have got deleted when you made the other changes ? Hope this helps.