Presently, due to limitations in the SCOM's method of passing data out, the only current way to integrate SCOM with PageGate is via Email and PageGate's GetMail module.
There are multiple methods of configuring GetMail to receive the traffic from SCOM but I think the method that would be best suited for your network and configuration is to have PageGate's GetMail module function as an internal-only mail server for SCOM to deliver alerts to/through. Now, I will say that I'm not familiar with the SCOM interface, so I don't know how to configure SCOM to deliver the alerts but I can tell you how to configure PageGate to receive the alerts that the SCOM system emails out.
Here's what you'll want to do:
Open the PG Admin.
Go to Program - Settings.
In the "Run on this Server" section, make sure GetMail is checked.
Go to Interfaces - GetMail - Settings.
In the Local Domain field, enter the internal IP address of the PageGate Server.
Put a check in Enabled, click on Apply and tell it Yes, you do want this to be enabled for all groups and recipients.
As soon as you do that, every group and recipient within PageGate becomes a valid email address on the new "domain". So, for example, let's say that the IP address of the PageGate server is 192.168.1.100 and you have an alerting group called priority_one. You could have the SCOM system email a message to email@example.com
and that message should reach the PageGate server, which would then read the message in and deliver it to the priority_one group's members as an SMS.