[F8] XPath not recognizing "." character in node path

I’m trying to create a tool that reads data in from a XML document. I’ve got the thing humming, generally working fine, but I’ve run into a specific problem when the path to a node includes a “.”
Below are two examples, one that is not a problem and one that is:

Not a problem:
GROUP[@TYPE=W44]/WSHAPE[@EDISTANDARD=W44X335]
Problem:
GROUP[@TYPE=M12]/MSHAPE[@EDISTANDARD=M12X10.8]

Notice the “.” in 10.8 in the path, which seems to be screwing everything up. Is there a work-around for this? This is the correct path to the node, and in all cases where the path doesn’t have a period the thing works fine.

Any thoughts greatly appreciated.