The default settings for RTCD should do the majority of Cisco devices. Does it work for any of your cisco devices? For me, I only had to custom write a RTCD rule for the Cisco Nexus devices.
I do it via the Syslog Viewer. (you can also do it via SNMP)
Do your devices send the appropriate config update syslog to Solarwinds? If yes, then just go into Syslog Viewer on your Solarwinds server and make sure the rule is turned on. All the rule does is look for syslog messages containing *Configured from console* and if it sees one, it triggers an external program to copy the current running config.
To get RTCD working for my Cisco Nexus device, I just copied the current rule and modified the Syslog Message Pattern to *Configured form vty*.
So with your other device, just see how they alert Solarwinds that the config has been updated. Then write your rule according to that.