First of all ISAPI_Rewrite installer ensures that ISAPI Filters and ISAPI Extensions components are installed in IIS.
here; it's called ISAPI_Rewrite3_00xx_x64.msi).
Then proxy handlers are registered in Handler Mappings snap-in.
That's all that is done by installer or (in a rare case when it fails) by you:) Now you may test ISAPI_Rewrite operation using this simple rule:
RewriteRule .? – [G]
Now let's turn on 32-bit applications compatibility mode (if you need to).
Click on the Application Pools node in IIS Manager: