Hi,
I know it's an old thread but here is my way to solve this kind of issues :
Just add a web.config file in the folder you want to exclude with this content :
<configuration>
<system.webServer>
<validation validateIntegratedModeConfiguration="false" />
<handlers accessPolicy="Read, Execute, Script">
<remove name="UrlRewritting" />
</handlers>
</system.webServer>
</configuration>
Best regards,
E.G.