NetMRI: Use Custom Field in Policy Rule

[#1]

We have some scripts that write info to custom fields when executed. I would like to make a rule that references those custom fields, like "custom_field_x must contain a value" or "number in custom_field_x must be greater than ___." Don't see how to do this. Please advise how to reference/use custom fields in policy rules.

[#2]

Looking at a way to do it via XML rule but not sure.

In the meantime:

I would use a Python script to read what's in the Custom Field and it wrong then generate a custom issue, run that as a scheduled job 

[#3]

Using separate script to read that custom field and set custom issue is a workable hack, so thanks for that.

Not ideal to have to run such a script against thousands of devies (even if it never gets to logging into them) at least daily (schedule like "every 20 hours"), so please do look into the XML rule route. That certainly would be preferred.