NSURLConnection http PUT with HTTP_RANGE not working - iphone

Question

I am trying to upload an image in chunks to the server from iphone, I have PHP code on the server side which reads the data and appends using HTTP_RANGE to an existing image.
Note : server side code is tested and running fine using html from browser.
My server side code only take POST as httpMethod, so I have to give restMethod = PUT and HTTP_RANGE in the body of the post, like this :-
[bodyData appendData:[[NSString stringWithFormat:#"\r\n\r\n--%#\r\n", kHttpPostMimeBoundary] dataUsingEncoding:NSUTF8StringEncoding]];
[bodyData appendData:[[NSString stringWithString:#"Content-Disposition: form-data; name=\"restMethod\"\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
[bodyData appendData:[[NSString stringWithString:#"PUT"] dataUsingEncoding:NSUTF8StringEncoding]];
[bodyData appendData:[[NSString stringWithFormat:#"\r\n--%#\r\n", kHttpPostMimeBoundary] dataUsingEncoding:NSUTF8StringEncoding]];
[bodyData appendData:[[NSString stringWithString:#"Content-Disposition: form-data; name=\"HTTP_RANGE\"\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
[bodyData appendData:[[NSString stringWithFormat:#"%d-0",offset] dataUsingEncoding:NSUTF8StringEncoding]];
The uploaded image is 0KB. I have also tried sending the file in one chunk only with restMethod = PUT and HTTP_RANGE=0-0, it still is 0KB, but if I only do restMethod = PUT and omit out HTTP_RANGE the image is uploaded successfully.
I am really stumped here, please help !!
EDIT :: Adding the actual HTTP Request :-
NSMutableURLRequest *req = [[NSMutableURLRequest alloc] initWithURL:url];
NSString *contentType = [NSString stringWithFormat:#"multipart/form-data; boundary=%#",
kHttpPostMimeBoundary];
[req addValue:contentType forHTTPHeaderField:#"Content-Type"];
[req addValue:msgLength forHTTPHeaderField:#"Content-Length"];
[req setHTTPMethod:#"POST"];
NSMutableData *bodyData = [NSMutableData data];
[bodyData appendData:[[NSString stringWithFormat:#"\r\n\r\n--%#\r\n", kHttpPostMimeBoundary] dataUsingEncoding:NSUTF8StringEncoding]];
[bodyData appendData:[[NSString stringWithString:#"Content-Disposition: form-data; name=\"restMethod\"\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
[bodyData appendData:[[NSString stringWithString:#"PUT"] dataUsingEncoding:NSUTF8StringEncoding]];
if (offset > 0) {
[bodyData appendData:[[NSString stringWithFormat:#"\r\n--%#\r\n", kHttpPostMimeBoundary] dataUsingEncoding:NSUTF8StringEncoding]];
[bodyData appendData:[[NSString stringWithString:#"Content-Disposition: form-data; name=\"HTTP_RANGE\"\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
[bodyData appendData:[[NSString stringWithFormat:#"%d-0",offset] dataUsingEncoding:NSUTF8StringEncoding]];
}
[bodyData appendData:[[NSString stringWithFormat:#"\r\n--%#\r\n", kHttpPostMimeBoundary] dataUsingEncoding:NSUTF8StringEncoding]];
[bodyData appendData:[[NSString stringWithFormat:#"Content-Disposition: form-data; name=\"file\"; filename=\"%#\"\r\n",fileName] dataUsingEncoding:NSUTF8StringEncoding]];
[bodyData appendData:[[NSString stringWithFormat:#"Content-Type: %#\r\n\r\n",mimeType]
dataUsingEncoding:NSUTF8StringEncoding]];
[bodyData appendData:fileData];
[bodyData appendData:[[NSString stringWithFormat:#"\r\n--%#--\r\n",kHttpPostMimeBoundary]
dataUsingEncoding:NSUTF8StringEncoding]];
NSString *msgLength = [NSString stringWithFormat:#"%d", [bodyData length]];
[headerParamDict setValue:msgLength forKey:#"Content-Length"];
[req setHTTPBody: bodyData];