Hi have just been looking around and by the looks of things the only way from which I can see is to convert your pdb files to pbf then convert pbf files to xml but I have no idea if it works but worth a try.
pdb to pbf tool:
http://wareseeker.com/Network-Intern....04.zip/333181
pbf to xml tool:
http://wareseeker.com/Network-Intern....04.zip/333280
These are just downloads I found quickly that are trial versions.