AssemblyResourceLoader not caching

[Clinton Ingram]

I have a simple aspx page running on the RTM .NET Framework 2.0 on Windows
Server 2003 SP1 that has a TreeView, some Validation controls and some
ImageButtons.

The page was returning slowly for clients on my WAN, and upon reviewing my
IIS logs, I can see that each request to the page is followed by _7_ requests
to WebResource.axd. I checked out all the files, and 4 of them are images
for the TreeView (which has display of all the images turned off -- not sure
why they're being asked for), and the remaining 3 are javascript files (one
for the TreeView, one for the Validation controls, plus the regular postback
script). The 7 files total over 50k of data being sent with every request
for this page.

I made requests for the files and examined the headers and found that the
server is sending a "Cache-Control: private" header for each of the 7 files
in question. I can see that the t= value on the query string is identical
for each request for the same resource (i.e. the entire query strings are
identical each time), and everything I can find says that the
AssemblyResourceLoader should be allowing them to be cached on the client.
Is there a config setting that affects this? I need to eliminate those extra
files if I am going to get resonable performance for my WAN clients...

Thanks!

-Clinton