Treeview HTC (MS related)

Asking here because someone might have tried this.  

The MS Treeview.htc control can be loaded from an 
inlined namespace.   So far so good.  The problem 
is that on a fairly large XML set of about 5600 
nodes, the load time is approx 60 seconds and that 
is on the local machine, not across the network.  Other 
than getting a faster machine, has anyone worked 
to speed one of these up?  I tried loading subtrees 
from functions, but that is worse overall.

Are htc web controls just slow beasties on load? 
That would be a shame because they are easy to 
integrate using a database source (ie, a generated 
document).

len