have to save updated EXBs under different file name

usas-annotation/insert-usas-annotations.xsl

@@ -48,7 +48,7 @@
             <xsl:variable name="doc" select="document($file-ref)"/>
             <!-- overwrite the document -->
             <xsl:for-each select="$doc">
-               <xsl:result-document href="{$file-ref}">
+               <xsl:result-document href="{$file-ref}.usas">
                       <xsl:apply-templates/>
                </xsl:result-document>     
             </xsl:for-each>