I had one posted that connected to the X5 (but the gps itself unplugs for plugin in with other compatible adaptors for the PDA bottom as you are aware). Do you still have the adaptor and is it still working that goes into the bottom of the X3. If you are interested let me know. I do not have any software or drivers with it and it is not doing me good sitting here. Obviously, you would pay for actual shipping and a reasonable price. (I will only ship to US addresses also).
Here is where I had it listed for the X5. PM me if interested for further discussion.
FS; Axim X5 Accessories