I have uploaded a plugin that you can download from sourceforge that works with ASP.NET2 : 
http://sourceforge.net/tracker/index.ph  tid=738747

details :

I added an extra tab to the default advanced image plugin named
'Browse'. From this new tab, you can browse all images
in a specific folder (and all subfolders) and view a
preview of the image. You can also upload an image to
the current folder.
to browse a specific folder in your web project you
must set an appsetting in the webconfig :
'tinyMCEImageBasePath'

eg. : 
<appSettings>
   <add key="tinyMCEImageBasePath" value="~/img/" />
</appSettings>

look at http://www.bradvincent.co.za/tinyMCE.jpg for a
screenshot



http://tinymce.moxiecode.com/punbb/viewtopic.php?id=4627