Admob AdSize for Ipad

Hi friends now i am developing Ads for Ipad,I am Using Admob.i have a small problem.

in admob documentation itself adsize in portrait view is 728x90.i want to change adsize to 768x90 to fit exactly in screen.i have changed frame by calling setFrtame for AdBannerView but it cant changes the size

*is it possible to change add size...? and at the same time i nee to show add in landscape with size 1024x90 *

Here is My Code
[AdmobBanner setFrame:CGRectMake(0,0,768,90)];     //Portrait
[AdmobBann开发者_开发百科er setFrame:CGRectMake(0,0,1024,90)];    //Landscape

Can any one help me to find the solution For this

AdMob currently supports only few ad dimensions. There is no way how to set your own size. Best thing to do would be to insert your ad into some kind of visual container with proper dimensions and fill rest of the screen with appropriate graphics