Update!
So, moved on from the Trap idea & reverted to good old email & building actions around that in ServiceNow. Have had moderate success, but as I've seen in other threads, the functionality for Solarwinds to assign a unique identifier to alerts is a work in progress at the moment, this would be key in tying alerts to existing records. Reason I mention this is that in the example above for Disk space alerting, we have a 3 tier (for want of a better description) system whereby as different thresholds are reached, alert emails are fired... the issue we have with this is duplication of ticket creation...
We are looking at somehow building a rule which would either create a new incident or update an existing one dependant on the ${variable} that Solarwinds can provide, but so far haven't been able to tie these together..
If anyone else has come across a similar scenario, I'd love to hear what you've done/explored/created in an effort to get something like this working... not necessarily just with ServiceNow either (as I'm sure whatever logic used could be translated across).
Thanks all