null subject attribute values are not returned

I believe null attribute values should return the empty string... here is the email:

Hi Penn Groups/Chris,

I've noticed that when subjectAttributeNames is passed to the web service the results are ambiguous if you specify multiple attributes.
For example if I search for a "PENNNAME,name" on group that contains both "pennperson" and "servPrinc" I get back for pennperson:

<ns:attributeValues>[pennname]</ns:attributeValues><ns:attributeValues>[name]</ns:attributeValues>

and for servPrinc:

<ns:attributeValues>[principle name]</ns:attributeValues>

It's unclear for servPrinc whether this means that the principle name is "PENNNAME", "name", or ???

I think it would be clearer if a null/empty item was passed back? like:

<ns:attributeValues>NONE</ns:attributeValues><ns:attributeValues>[principle
name]</ns:attributeValues>

or

<ns:attributeValues></ns:attributeValues><ns:attributeValues>[principle
name]</ns:attributeValues>

using "NONE" poses it's own problem, and I'm not sure what various soap clients will do with an empty element.

This isn't a problem for me, b/c I'll generally only be using "PENNNAME", but I thought it might cause others problems.

-eric