StaticFileHandler should work. I had the same problem with *.bz2 files and I have solved it using StaticFileHandler. You can find configuration I used below:
<httpHandlers>
<remove verb="*" path="*.asmx"/>
<add verb="*" path="*.asmx" validate="false" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
<add verb="*" path="*_AppService.axd" validate="false" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
<add verb="GET,HEAD" path="ScriptResource.axd" type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" validate="false"/>
<add verb="*" path="*.mvc" validate="false" type="System.Web.Mvc.MvcHttpHandler, System.Web.Mvc, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
<add verb="*" path="*.bz2" type="System.Web.StaticFileHandler" validate="false" />
</httpHandlers>