Sorry for taking so long to get back to you on this:
I just tried this and at the moment it doesn't work.
Although since I already use RA & Dec for galaxy positioning so it should be an easy fix to add support in the XML system files.
Once it works it will most likely work like this:
<Body>
<Object>Neptune</Object>
<RA>17:45:40.045</RA>
<Dec>-29:0:27.9</Dec>
<Distance>1 au</Distance>
</Body>
What are the RA & Dec # that you have?