Hello,
I don't know exactly which features are you missing in WHD, however you can also try Alert central at Alert Central - Free Alert Management Software by SolarWinds . The alert/ticket updates should work here in 2 ways (Acknowledge/Notes adding) similar way as for WHD. For a bit more programatical approach you can try Orion SDK - more info here: Orion SDK Information - it gives you the API for working with Orion via the SolarWinds Information Service.
Regards,
Honza