Setting cross-domain cookies in Safari

From the Safari Developer FAQ:

Safari ships with a conservative cookie policy which limits cookie writes to only the pages chosen ("navigated to") by the user. This default conservative policy may confuse frame based sites that attempt to write cookies and fail.

I have found no way to get around this.

If it's worth anything, Chrome doesn't set the cookies either if you use the <script> appending method, but if you have a hidden <img> with the same source, Chrome works in addition to the rest of the browsers (except, again, Safari)

Here is a solution which works:

http://anantgarg.com/2010/02/18/cross-domain-cookies-in-safari/