What I've done in the past is to insert a direct link to the SR on SharePoint. This way you just need to maintain the link on SharePoint and avoid messy integration. The link will not change if you are making modifications but if you republish the SR then you need to update the URL (at least that's what happens in ITSM v7.x.x). You can easily get the URL for the direct link on HEAT 2015 from the SR itself (see below). Mind you, this is just a very simple way to submit a SR from SharePoint and there is not pushing of information between the systems.
Thanks for the reply. I was hoping to pass contents of the SR back and forth.
I don't know of any way to do this from HEAT... yet. I used to do something similar with ITSM 6.x for SharePoint record creation though. There used to be a quickaction type that allowed you to fill out a web form. You could enter in the "new item" URL of that SharePoint list then ITSM would let you configure what fields from ITSM were to populate in which field on the SharePoint list.
I was disappointed to find that this was not included as a feature in HEAT, but I think that it's because it's web-based and there are some security concerns.
If you're trying to update existing SharePoint items, then that one might be a little trickier. Good luck with your search. This would be a good enhancement to request if you decide to go that route.
I am a Software Developer and have done some integration work with Heat in the past. Not sure exactly what you are trying to accomplish, but I think you can easily write a webpart that can extract information from the Heat API and update information also. I wish you the best on your search for a solution. The would be a great Heat feature. Take Care and Have a Great Day.