I'm using lytebox to open an iframe, but the iframe url is in another domain that the parent window.

i need to close the iframe when user clicks a button. I can do that with javascript : top.$lb.end();
the $lb.end(); starts lytebox scripts in parent window which close the iframe and modify all the css stuff.
That works when my iframe url is in the same domain. But when it's in another domain, that does'nt work.

Can anyone tells me how to do that ? Starting the $lb.end() function of the parent window ?
Thank you.