As a small note, if you do tend to 'upload' binary data with ASIFormDataRequest, and your binary data is dynamically created and stored in, for example, a tmp folder, noted as an NSURL.
These lines of code might save you a few minutes.
NSURL* url = ....;
[request setFile: [url relativePath] forKey: @"somePostKey"];
[request startSynchronous]; //or async.