We have a ASP.NET site which is using squishit with # appended to the end of the name of the newly generated file. This project is calling another PHP site which is hosted on an outside server. Is there a way to call the generated js and css bundles from our PHP site?
Not really, you can link to the asset statically but have no way to figure out what will replace the #. Your best bet is probably to switch to querystring invalidation (just remove the '#' from your output filename) and figure out a way to ensure that the right version is retrieved in the PHP app (easier said than done if they are deployed separately).