[xsl] Variables and more than one document

["White, Clinton" <whitec@xxxxxxxxxxxxxxx>]

I am working with XBRL instance documents

For each element in an XBRL instance document, I need to find the
associated label in another document
For each element in the first document, I create a first-variable and
select the element's local-name( )
I then create a second-variable and concat('label','_','first-variable')
I then try to find this second-variable as an attribute in a second
document AND I get zero results

Is my variable out of scope when I go into the second document?
What might be a solution?

Thanks - Skip