[TagZilla] How do I change maxversion?

[He Who Seeks]

I have read past messages to this list about how easy it is to make 
Tagzilla work with Thunderbird 1.5.  I have installed jslib.  When I try 
to install the tagzilla xpi with the extension manager, it tells me it 
can't do it because it is not compatible with TB 1.5.  This seems to be 
a catch-22.  If it doesn't install, how can I edit the install.rdf? 
Could someone walk me through this step-by-step?  I must be missing 
something.

Thx,
Bob