Mouse over - Button visibility - 2.49b

Hi,
I am trying to make a button, so that when I mouse over it the the button over image will show. I mean I hv two images for the button. one is simple button and another is up button.
I want to change the visibility state of the buttons. Like on mouse over, simple button image will get invisible and over button image will get visible. And on mouse out, up button will become invisible and simple button will get visible. Kindly help please.

regards

Set the simple button to be visible when not on mouse over -select inv option, and invisible when mouse overed… Visa versa for the up button… Like you said yourself…

But there is no mouse sensor called mouse out. thats why it does not reset it when i mouse out from the image. it set the up image to be visible forever and simple image to be invisible. any other way?

regards

mouse over
-> AND -> visible
-> NAND -> invisible

@Monster:
It is easy but I would never be able to solve it myself, thank you.
@im8act:
Thank you also fro your reply.

regards