Grouping using information from a dtd ?

I have the following problem:

I want to sort data from a XML file using information conatined in a DTD.

In the DTD there is a definition for an attribute like:
<!ELEMENT taskName                 (#PCDATA)>
<!ATTLIST taskName                 activity ( proposal |
			 	     requirementSpecification |
                                   abstractDesign | detailedDesign |
                                   testSpecification | implementation |
                                   moduleTest | integrationTest | systemTest |
				   validationTest |
                    documentation | releaseAndDeployment ) #REQUIRED>



Now I want to sort a xml file which looks like:

<taskElement>
	<taskName activity="moduleTest">Test1</taskName>
</taskElement>
<taskElement>
	<taskName activity="proposal">Test2</taskName>
</taskElement>
<taskElement>
	<taskName activity="moduleTest">Test3</taskName>
</taskElement>
<taskElement>
	<taskName activity="abstractDesign">Test4</taskName>
</taskElement>




The output should be sorted using the sequence given in the DTD !!!
So it should look like:
1) proposal: Test3
2) abstractDesign: Test4
3) moduleTest: Test1, Test2



It should not be the order they are opresent in the XML file (here: 
moduleTest: Test1, Test2, etc.)
NOR should it be a sorted order using <xsl:sort ...>




How can I accomplish this ??
Do I have to specify an additional XML file, containing the attribute values 
in th correct order or is ist possible to use somehow the information in the 
dtd ??

Thank you for any help or suggestions !
Peter Biechele

#####################################################
Dr. Peter Biechele, E-Mail: Peter.Biechele@xxxxxxxxx


 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list