[DAS2] URIs for coordinates

[Helt,Gregg]

I'm editing the spec docs to clarify use of coordinates.  Where can one
find the URIs a server should use for the uri attribute in a COORDINATES
element?  I've looked at the HTML summary at
http://www.dasregistry.org/help_coordsys.jsp , but this doesn't list any
of the actual URIs I'm seeing used in the DAS registry.  For example,
http://das.sanger.ac.uk/dasregistry/coordsys/CS_SPICEDS5 for NCBI human
assembly v35 from the DAS/2 registry sources doc:
 
<COORDINATES
uri="http://das.sanger.ac.uk/dasregistry/coordsys/CS_SPICEDS5"
taxid="9606" source="Chromosome" authority="NCBI"
test_range="chrX/29721943:31932065" version="35"/>
 
or http://das.sanger.ac.uk/dasregistry/coordsys/CS_DS5 for the same
assembly from the DAS/1 registry sources doc: 
 
<COORDINATES uri="http://das.sanger.ac.uk/dasregistry/coordsys/CS_DS5"
taxid="9606" source="Chromosome" authority="NCBI"
test_range="12:13019000,13019800" version="35"/>
 
Also, shouldn't these be the same URI?
 
            thanks,
            Gregg