That's all I use and it works fine... for the most part. I have noticed that sometimes (only with C0peac for some reason) SubIDs will either not track or be gibberish. For instance I'll have subIDs that are 103, 104, 105, 106 etc and then one is 742923 - Of course the gibberish one happens to be a sale so I have NO idea where it came from.
try this:
www. cpaclix.com/secure.asp?e=ABC123&d=0&l=0&p=0&o=SUBIDHERE
A lot of DirectTrack networks keep the subID in the o variable. I'm not positive though so test it first.