I thought it might be a bit of a longshot. The settings I'm referring to are accessed by actually entering the IIS manager program on the server. With shared hosting, they probably wouldn't want to give you access or make changes to that because it might limit them to 45 instead of 50 web sites hosted per box.
In any case, using the AppKeepAlive task should prevent the site slowdown after no activity for a period of time.
Jamie