[mythtvnz] Mapping EPG to DVB-T channels

[Tony Peguero]

Hi all.
I have been setting up a Mythbuntu system with a pair of DVB-T cards. I 
am able to scan for channels and watch them, but I'm struggling with the 
EPG setup and I could really use some advice.

I've followed the tv_grab_nz-py mini howto, but it doesn't seem to be 
working correctly. Or maybe I just don't understand how it is meant to 
be used. I selected the grabber in "Video Sources", and answered yes or 
no to each channel at the terminal, all according to the howto. After 
running mythfilldatabase, I went back into MythTV Setup, and now the 
Channel Editor lists both the previously scanned channels and the 
channels from the grabber, resulting in many duplicates. But, as far as 
I am aware, the grabbed channels don't contain any frequency 
information, so they are not watchable. The scanned channels are 
watchable, but have no EPG information. So, I tried manually filling in 
the XMLTV ID fields on the scanned channels, using the same values as 
the grabbed copies. At first I thought this worked, as now when I'm 
watching TV the EPG shows data for every channel. But, I then noticed 
that the channels are all swapped around, apparently at random. Here is 
what the EPG is showing:
TV1 (1) showing data from Stratos
TV2 (2) showing data from TV3
TV3 (3) showing data from C4
C4 (4) showing data from TVNZ7
TVNZ6 (6) correct
TVNZ7 (7)showing data from TV2
SPORTEXTRA(20) showing lots of unknowns (probably correct)
I've double checked that each channel has the correct XMLTV ID assigned.

I don't understand what the proper procedure is for setting up these 
channels. What am I doing wrong?