ASIHTTPRequest: Encoding in post data

I'm using ASIHTTPRequest to send a form this way:

ASIFormDataRequest *request = [[[ASIFormDataRequest alloc] initWithURL:url] autorelease];
[request setPostValue:foo forKey:@"post_var"];

How can I set the encoding of the nsstring foo??

The web receiving the form data expects the value in ISOLatin1

From stackoverflow

• const char *_cFoo = "bar";
  NSString *_foo = [[NSString alloc] initWithCString:_cFoo encoding:NSISOLatin1StringEncoding];
  ASIFormDataRequest *request = [[[ASIFormDataRequest alloc] initWithURL:url] autorelease];
  [request setPostValue:_foo forKey:@"post_var"];
  // ...
  [request trigger];
  [_foo release];
  

  EDIT: I'm not sure why the above wouldn't work. I guess I should try it out. But looking at the source for ASIHTTPRequest, the -setPostValue:forKey: method looks like it takes any NSObject subclass for a POST value:

  - (void)setPostValue:(id <NSObject>)value forKey:(NSString *)key
  {
     if (![self postData]) {
         [self setPostData:[NSMutableDictionary dictionary]];
     }
     [[self postData] setValue:[value description] forKey:key];
     [self setRequestMethod:@"POST"];
  }
  

  Perhaps convert an NSString to a C string and use its NSData representation as the POST variable value:

  NSString *_foo = @"bar";
  const char *_cFoo = [_foo cStringUsingEncoding:NSISOLatin1StringEncoding];
  NSData *_cFooData = [NSData dataWithBytes:_cFoo length:strlen(_cFoo)];
  [request setPostValue:_cFooData forKey:@"post_var"];
  

  Jorge : The point is I already have an UTF8 encoded NSString. Following your example: c_Foo = [foo UTF8String]; ...... It's not working. I dont get ISOLatin1 encoded strings :-(

  Jorge : Doing that, I get values like this: <6275656e f3212121 2121> in the form receiver.