You can build a custom Integration to ‘cover the gaps’ so to speak, managing your connections via the Integration Service is really nice instead of having to manage tokens in your own library.
Too late now I know, but food for thought for the future.
The Integration service stuff is for sure lacking alot of stuff, but especially now they started adding a generic ‘HTTP request’ activity for most connections you can now cover most of the gaps without re-inventing the wheel as was said.