Waiting on Sockets or File Descriptors

Hi, I have the following problem: I use an external library through the foreign function interface which gives me _several_ sockets and expects me to call it again when any of those sockets becomes readable or writable. Since I know that the Haskell run-time system has all the required functionality in place, I wonder whether there is any way to register these sockets in the internal scheduler and have it call an 'IO ()' function in case of such an event? What makes matters more complicated is that the _library_ owns these sockets -- not me. So I cannot really touch them or lift them into a 'Handle'. Any ideas? Peter