On my crystal I removed the front panel (3 clips on the inside of the xbox, 2 on the sides), then threaded the cable through the front left clip hole, and stuck the XLed flush under the the dvd drive so the left sides of both the dvd tray and the xled were lined up.
Looks really good

The real trick was finding the two side clips
some guy put his external led right under his jewel so his jewel will be the color for the bios... brilliant!
Can you post a picture or diagram?
(I have some pictures I took while I mounted mine... will try to get them online

)
I will try on the next install I do...
try