Can't read/write to properties of an Objective-C class from within a CGPDFOperator C function

Question

OK, so I'm using C callback functions being run from a CGPDFScanner. These functions are within a class called PDFContentStreamProcessor with an NSMutableArray property called myArray

ARC is enabled, but I made an exception in the build phases for this class.

void RandomCallbackOperatorFunction(CGPDFScannerRef s, void *info) {
    PDFContentStreamProcessor * searcher = (PDFContentStreamProcessor*)info;
    [searcher setMyArray:[[NSMutableArray alloc] initWithObjects:@"aString",@"AnotherString", nil]];
    NSLog(@"arraylength:%i",searcher.myArray.count);
}

It finds text, integers and objects just fine, but I can't do much with the values if I can't store them anywhere. Any ideas?

I've also tried it this way:

[(PDFContentStreamProcessor*)info setMyArray:[[NSMutableArray alloc] initWithObjects:@"aString",@"AnotherString", nil]];

... also with no luck