There's someone on maemo forums that seems to have done something similar with you. Check the link, his post includes a download link of the compressed img.
It works on my N900 with a 'tiny' problem:key mappings of N900 doesnt seem to work correctly in BT.
Edit:Gave a shot at the img from the link you gave. Working fine on my N900-still messed up keyboard though-but was kinda slower from SuperDump's from Maemo forums.