Hi, i need some help

I'm trying to upgrade my N810 to Diablo using the "Nokia Internet Tablet Software Update Wizard" with the downloaded Diablo image file.

but it seems that my N810 is locked to the ISP version "2.2007.51-3.4Singtel"

The software wizard shows "unsupposted software update" after i choose the Diablo image file.

Is there anyway to upgrade to the Diablo version on my N810?

Thank you very much in advance , i'm quite new in Maemo here.