I haven't thanks for the tip

I checked for the first value and I couldn't find it. However
I did a quick search and I did find that string in default.xbe perhaps this will help. I'll give it a try when I get home
If I understand that thread correctly, it looks like that only disables the check to see if the content is right. It still checks to see if the content is signed to your eeprom. Hopefully I'm wrong. I guess they got around that in Halo 2 and a bunch of other games though, not sure how. But do you actually have the DLC files? What format are they in?