Ok, I finally had chance to test bunch of oryginal N900 camera modules, and - guess what - there are two types of them! One is easily disassemble'able, and it's the on on azkay's photos. The other-looking one is, OTOH, utterly impossible to open without breaking it to pieces, so if you got that type, don't even try. Unless you're better than me and figure out a way, then, by any means, share it with us.

In other case, it's required to get same-looking module as azkay's, to do successful disassembly and IR filter removal.

/Estel