Hi:
That is a very common problem with the Treo 650 model due to a poorly designed headphone jack. I am not sure if the 700 has the same issues. A search of these boards using "headphone jack" as the search term will give you a number of threads about this problem. Here is one link to get you going:
http://www.everythingtreo.com/forum/...50-a-7902.html
Regarding the volume issue, VolumeCare is the defacto solution people around here seem to use. You will find that available in the EverythingTreo Software section. VolumeCare is also said to resolve some of the headphone jack issues. You can also search the boards for VolumeCare and find lots of information.
Oooops! I just reread your post and you were asking about bluetooth volume. Sorry, but I am not sure if that can be helped by VolumeCare. I am lucky that the volume issue is not one that I have experienced so I haven't tried any solutions.
Let us know how you make out.
SteveTaz