flashing message in all PM pop-ups

[cashpath]

Can someone tell me how I would add a flashing message to the pop-up window that pops-up and tells people they have a new Private message??

Thanks

[NTLDR]

You can't as far as I'm aware as its just a standard Javascript confirm box.

[cashpath]

Ok is there any way I could insert a flashing message into every PM sent (at the bottom like a sig) Every PM from every user would have this attached to it and they could not remove it?

[cashpath]

Sorry for the double post, but can anyone tell me how to ad the flashing sig to all pms (doesn't even have to be flashing if that can't work just a sig.. ?? )