After looking over cotojestwtf's proxy it seems to only support spoofing EU region PS3s. I was reluctant to say this, but Sony were going to find out anyway, the spoof is quite simple. Basically authenticating to SEN is the same between 4.00 and 4.10, the PS3 simply checks to see if it is on the latest FW by comparing it's firmware version to that of the ps3-updatelist.txt.
So using a 4.00 ps3-updatelist.txt for your region lets you go online on 4.00. So to make this work for your region download this ps3-updatelist.txt (delete the region entries you do not need), use your favourite ps3 proxy, and redirect the update list to this one.