Can you have a Parameterizable LOCATION for a %Stream.FileCharacterGzip property?

I want to make the LOCATION for a %Stream.FileCharacterGzip property we have in a class parameterisable (as in stored in a global), so it can be different for different customers. Is that possible?  I've tried doing it a few different ways:
Creating a parameter
Parameter STREAMLOC = {^websystem("auditstream-location")};
then I tried to reference that in the 

Property HTMLZIPDoc As %Stream.FileCharacterGzip(LOCATION = ..#STREAMLOC);

but the compiler doesn't like that. 

I've also tried adding something to %OnOpen and %OnNew:
Method %OnOpen() As %Status [ Private, ServerOnly = 1 ]
{
    S ..HTMLZIPDoc.%Location=^websystem("auditstream-ziplocation")
    Quit $$$OK
}

Method %OnNew() As %Status [ Private, ServerOnly = 1 ]
{
    S ..HTMLZIPDoc.%Location=^websystem("auditstream-ziplocation")
    Quit $$$OK
}

but that didn't work either. Is it possible?