It's one of the "issues" that new HDV format brings to us. The higly-compressed format os MPEG2 is too hard to "separate" frame by frame individually because they are dependent each other. There a GOP train of frames that most of them just contain very little information inside it, "copying" the rest from I-frames.
I don't know if with these new HDV solutions from Matrox, Canopus and Pinnacle can cross this problem without hassles.
I'd request for you that have been using HDV already that maintein us informed of your problems and advances on HDV editing.
Abit IC7 - P4 3.2C - 1GB RAM - RAID 0 2x80 GB Seagate HD - Matrox RTX100 - LG T910B 19\'