On reading through the latest kmttg documentation I noticed that three days ago a new version of tivdecode was release, and it support the TS MPG streams that NZ TiVos copy off their files in.

I have run a test and copied off a file which worked, then re-cut it into an H.264/MKV which looks great.

Up until three days ago I would have said use VideoReDO, but tivodecode is FREE so get in there and use that instead.  It also integrates nicely into kmttg.  Links for both programs are here ...

http://code.google.com/p/kmttg/downloads/list

Enjoy!