mail availability control

Hi experts,

I have the following issue.

I have activated budget availability control in PS and I choose the action "send mail to responsible" when the defined tolerance is exceeded.

The mail is sent to the sap Office.

I want to know:

1) Is it possible send the mail to external mail address? if yes, how?

2) The mail isn't sent to the recipient as an express message. Can I have an express message?

Thanks in advance for your help

Regards

Raffaele