Post Data to Webservice URL - objective-c

Question

I have problem with my code for posting data to webservice.
Can someone please, tell me where I am going wrong.
I need to post three fields (doctorId-STRING, patientId. STRING, date-STRING) to this address:
http://www.walter-dev.com/doctor/public/setTermin
How to make this right?
NSString *post = [NSString stringWithFormat:#"&id_doktor=%#&id_pacijent=%#&datum=%#",#"iddoktora",#"idpacijenta",#"ovojedatum"];
NSData* postData = [post dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];
//You need to send the actual length of your data. Calculate the length of the post string.
NSString *postLength = [NSString stringWithFormat:#”%d”,[postData length]];
//Create URLRequest object and initialize it.
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];
//Set the Url for which your going to send the data to that request
[request setURL:[NSURL URLWithString:[NSString stringWithFormat:#"http://www.walter-dev.com/doctor/public/setTermin"]]];
//set HTTP method (POST)
[request setHTTPMethod:#"POST"];
//Set header field with lenght of the post data
[request setValue:postLength forHTTPHeaderField:#"Content-Length"];
//I dont understand this line of code
[request setValue:#"application/x-www-form-urlencoded" forHTTPHeaderField:#"Current-Type"];
//Set httpbody of the urlrequest with string "post"
[request setHTTPBody:postData];
//Initialize object with urlRequest
NSURLConnection *conn = [[NSURLConnection alloc]initWithRequest:request delegate:self];
if(conn)
{
NSLog(#"Konekcija prema serveru je uspjela");
}
else
{
NSLog(#"NIJE USPJELA ");
}