If your sure that its recognised properly then have a look on this links page http://www.holtmann.org/linux/bluetooth/
The only thing i can think of to fix if it isnt recognised by linux is the following:
Firstly you have to find out what chipset your bluetooth dongle uses.
Secondly i think your going to have to basically compile your own kernel and include the module for the chipset that your bluetooth dongle uses.
Thirdly depending on if you add it to the kernel or as like built in you will have to add the name of the module to a config file which is used when you boot linux.
If the kernel doesnt have support for your bluetooth dongle then you can either try and find a different copy of the kernel which does or try and find the driver for it.
To recompile your own kernel however requires a whole guide itself , plus different linux distro's will have different kernels with different options and slightly different config files.
Only thing i can suggest is going to www.gentoo.org
and reading through their handbook, its basically step by step setting up linux manually, in the handbook there is a page or two on recompiling your kernel for your particular configuration.