MFMailComposeViewController customize send button

Question

I need to be able to change both the background color and the title color for the UIBarButtonItem "Send" on the MFMailComposeViewController.

Changing the customView property force it no longer to behave.

Sample code:

MFMailComposeViewController* vc = [[MFMailComposeViewController alloc] init];
vc.mailComposeDelegate = self;

//This fails:
[self.navigationController presentModalViewController:vc animated:TRUE];
self.topViewController.navigationItem.rightBarButtonItem.customView = 
     [self makeMyView];

Also by overriding properties (target,action) to my method. This too is no longer called.

Is there a way to override the customView on this button?

I'm supporting iOS4 otherwise I wouldn't be in this trouble & I don't have the time at the moment to integrate a full SMTP client such as SKPSMTPMessage.