i was trying to do this several weeks ago. i got sidetracked by some other work.
ive got some step by step instructions for VSTS/Git. if youre happy to use VSTS/Git combo i will post them tomorrow. like i say i never finished cos of other work, but i do have some good instructions to do this. before you start i would consider all the directory structures for you projects and supporting test evidence etc. as once you convert your project to composite and add the project into your vsts/git repo you quickly use up the allowed 260 characters in the full path length.
the instructions are just for getting it into a VSTS/Git repo - so don't forget any of the soapui project preamble you need to do (shorten all the foldernames, project names, testsuite names, testcase names, teststep names, convert to composite project etc.) needs to be done BEFORE you start using the instructions.
As I said in my previous post - I hit a character limit (I think its about 265) because I have so many different projects with lots of sequential versions of testdata that were making the full path very long - so make sure you seriously consider this before hand.
If you're paths are too long, when you try and convert to composite, you'll get a warning it doesnt work if you hit the limit.
HOWEVER - adding into a VSTS/Git Repo adds additional chars to the full path length - so make sure you well UNDER the character limit - you don't know what will happen in the future and future project work could add to the path length quite a bit if you don't organise your stuff properly