xsl:document href attr: attr value templates?

I can't figure out from the 1.1 WD whether I can use an attribute
value template in an xsl:document element's href attribute. For
example, can I do the following?

  <xsl:variable name="var1">1</xsl:variable>
  <xsl:document href="file{$var1}.xml">
    <!-- document contents here -->
  </xsl:document>

thanks,

Bob DuCharme          www.snee.com/bob           <bob@  
snee.com>  "The elements be kind to thee, and make thy
spirits all of comfort!" Anthony and Cleopatra, III ii