(iOS) How to make the custom keyboard background transparent

Question

As title, how do I make it transparent for iPad?
because it is too ugly to see gray color outside.
Thanks.

Regards,
GRTan.

Screenshot:

EDIT:
Sorry that I forgotten about the source code.
Source Code Here.(UPDATED)

Answer 1

Insert following line

defaultLNNumberpad.backgroundColor = [UIColor whiteColor];

after

defaultLNNumberpad = [[[NSBundle mainBundle] loadNibNamed:@"LNNumberpad" owner:self options:nil] objectAtIndex:0];

in your LNNumberpad.m file.

http://i.stack.imgur.com/wLQOj.png