Windows 7: Trying to make an unattended .mps install

Hey everyone.

I'm currently trying to silently deploy an Adobe Reader Update pack wich comes in a .msp file.
My problem is that the "Open File - Security Warning" prompts me everytime.

Is there a trick or some kind or parameter that disables this?
Preferably without making changes to the registry, group policy or worst of all reboot.

Cheers in advance.

I take it that there is no known way to do this.