You could add the following handler to the <handlers>
section of your <system.webServer>
:
<add
name="ManagedDllExtension"
path="api/nav/*/*.dll"
verb="GET"
type="System.Web.Handlers.TransferRequestHandler"
preCondition="integratedMode,runtimeVersionv4.0"
/>
This will make all requests containing .dll
be served through the managed pipeline. Also notice how I have limited them only to the GET verb to limit the performance impact.