Threshold line in Health graph

I have added a new count health metric, and was trying to add a line to the graph with a fixed value, provided by another OID:

count:
            data:
                -
                    oid: vsxCountersConnNum
                    value: vsxCountersConnNum
                    num_oid: '.1.3.6.1.4.1.2620.1.16.23.1.1.2.{{ $index }}'
                    index: 'vsxCountersConnNum.{{ $index }}'
                    high_limit: 'vsxCountersConnTableLimit.{{ $index }}'
                    multiplier: 1
                    descr: Number of active connections
                    state_name: vsxCountersConnNum

This did not work, does anyone know how to set this up? The graph is being plotted, but without the high_limit indication. I have also tried using the OID instead of the metric name, but it also failed.

Thanks!

OS definitions are cached… run ./discovery.php with the -d option which automatically clears the cache.

Thank Murray, I will try that.
Would it be ok to use both OID and metric name?