Unfortunately it seems the iPhone Kindle app does not support the KF8 format... yet... the KF8 (AZW3 files renamed as AZW) cannot be downloaded on my iPhone, the download stops at about 97%...
So either I'll have to forget about the iPhone (I'll probably do this, when my touch will arrive I'll never read again on the iPhone anyway) or I'll have to find a way to have a combined KF7/KF8 file but without the kindlegensrc.zip file