XML : XSLT transformation: accessing inline mapping

I am having problems with inline structure and accessing it in xslt:

I have written a transformation which is transforming xml to xml. For some values i have to look up a key-value-mapping, which i have specified in my stylesheet like this:

  <map:mappings>     <mapping doi="DOI_VALUE1" name="NAME1"/>     <mapping doi="DOI_VALUE2" name="NAME2"/>  </map:mappings>    

In my transformation i will access this mapping like this:

  <elementXY>     <xsl:value-of select="document('')//map:mappings/mapping[@name=$var]/@doi"/>  </elementXY>    

This is working great, but as 3rd party software is involved -which does not like the "document('')" function- i am looking for another possibility/alternative.

If additional information is required, i am happy to give it. Thanks in advance!