IPhone - leaks in MessageUI infrastructure?

I use MFMailComposeViewController to send emails in my application.
When I launch my application using Tools ,
I see a leak after I clicked to send an email.

Leaked Object   #   Address Size    Responsible Library Responsible Frame

MutableMessageHeaders,1 0x6be950    32 Bytes    MessageUI   +[MFComposeTypeFactory headersFromDelegate:]

_MFOutgoingMessageBody,1    0x1190ed0   32 Bytes    Message -[MessageWriter createMessageWithPlainTextDocumentsAndAttachments:headers:]

Do you know how to fix
this , is it a leak in the MessageUI infrastructure?

- (void)showMailComposer
{
        MFMailComposeViewController *picker = [[MFMailComposeViewController alloc] init];
        picker.mailComposeDelegate = self;
        [picker setSubject:@"Subject"];
        NSString *emailBody = @"Email body";
        [picker setMessageBody:emailBody isHTML:NO];
        [self presentModalViewController:picker animated:YES];
        [picker release];
}

#pragma mark -
#pragma mark Dismiss Mail/SMS view controller

    // Dismisses the email composition interface when users tap Cancel or Send. Proceeds to update the 
    // message field with the result of the operation.
    - (void)mailComposeController:(MFMailComposeViewController*)controller 
              didFinishWithResult:(MFMailComposeResult)result error:(NSError*)error 
{
            [self dismissModalViewControllerAnimated:YES];
    }