problems with external xref in xml

I'm having problems with external xrefs while importing xml files into FrameMaker 11. My internal xrefs are working correctly.

I would like to create this link to the external xml file within the same folder. I have edited my structapps file to use xml for xref.

Any help would be appreciated.

My xml is:

<english><xref refbook=”filename”/></english>

My read/write rules is:

element "xref" {

               attribute "refbook" is fm attribute "linkend";

               attribute "refbook" is fm property cross-reference id;       

               attribute "format" is fm property cross-reference format;

}