Videomic and HD2
 

I know I posted this in the HD2 forum but I need an answer very soon as I will be unable to get on the internet from wednesday for a week and that is when I will be using the camera. I bought a videomic for my HD2 and, while the sound is better and there is no camera noise, the sound from the mic is very quiet and there is a hiss which is really quite annoying.
I am very much a beginner with this so I don't know what to do.
My settings are external mic vloume 4-5 (out of 5). Putting the mic on high pass doesn't seem to make a difference, nor did fiddling with the switches in the battery compartment.
Could it be the battery? I did just out a new one in but you never know! If anyone has had experience with the HD2 and videomic then input would really be appreciated. Any advice at all would be great.
Toby