How may I add an OK box to the forum Submit success message?

How may I add an OK box to the forum Submit success message?

Else replace that message pop-up with a true dialog box having an OK box?

I need this to solve the problem that the current pop-up disappears automatically after a couple of seconds and this is too short a time for some of my users.

I do not want to use a second form since I need access to the input.XXX properties.

Thanks.