I found that I could not use setTo: with non-Objective-C parameters (such as for -[NSFIleManager fileExistsAtPath:(NSString*)path isDirectory:(BOOL*)isDirectory])
On my local copy, I added a setValueTo: which takes an NSValue, creates an OCMPassCTypeByRefSetter (copied from OCMPassByRefSetter), and use that to set the resulting C value in OCMockRecorder.
Patch available upon request.