Got more info from another forum. This might hepl other Senn100 G2 users...
Radio mic always puts another layer (or two) of levels settings in the audio chain.
1) In the transmitter you have to set the levels or gain (SENSIT in the menu) so, that the loudest sounds do no overload the transmitter. The setting is quite coarse in steps of 10 dB, from 0 to -30 dB. With the standard lavelier it is usually -20dB, or -10dB if there is only quiet conversation expected. Lower -20dB setting is safer, if the sound level is high enough to overload the transmitter the case is lost in the beginning and can not be helped later. There is the levels meter on the transmitter, the last segment means overload and there is also the yellow AF PEAK light which never should light up.
2) On the receiver end you have to set the level with which the reciever puts the signal out to camera or recorder: mic or line level. There are no two settings for this, but the AF OUT menu choice lets you set the level from -30dB to +12dB in steps of 6dB. If you want to use line level signal (+6dB or +12dB) you should set the camera inputs to LINE (front of the DVX100) and use high AF OUT -levels like +6 or +12dB. This bypasses the mic preamps on the camera and is the better choice. If you insist in using mic level signal, you should try -30 or -24dB levels and set the camera inputs to MIC. Whith either setting the audio level dials should work at the normal 11-12 a'clock position and give normal working levels with some red lighting up at the loudest passages.
With just the camera (or recorder) you only have to worry about one level setting, with radio mics you have to worry about two level settings, plus have to make sure the signal levels are right fot the chosen input mode in the camera (mic/line).
One more thing to note - when you swap out the batteries, as you should before every shoot, the unit will reset and lose your settings, so remember to go back through everything so you don't get crappy results.