Hi Jonathan,
I looked through the CA Service Management docs....
I think it would be best to open a ticket to the Service Management group to see what interface they recommend.
For the basic case it looks like they have a command line interface.
I think it would be possible to
1) Install an agent on the Service Management server.
2) Create a shell script that accepts the MN variables and issues the command to Service Management.
3) Create an ALERT that will initiate a job and pass the MN variables into the script created in step 2)
It is also possible to enable the Service Management "mail eater" . Then an E-mail can be sent to it in a special format and it will read it.