Well, the log shows that the monitoring was started, so how often is it
supposed to check?  That should be specified in your sermon.conf file.  By
default it's 20 minutes I think.  So you might have to wait awhile for it
to kick off and notice the outage.
You can also modify the properties file and change where it says INFO to
TRACE and see whether you can get servmon to trace what he's doing to the
log file.  And if all else fails, call Support.  That's why they are there

James Shanks
Level 3 Support  for Tivoli NetView for UNIX and Windows
Tivoli Software / IBM Software Group