Make build results(couple of string) available via API

Hi, I have a build which perform merge of two Git branches, as a result I have two variables inside my app(two strings):
1) merge commit sha1
2) new commit tag

I what to make this values be avaliable via TC HTTP API.

What I tried:
via https://<TC_HOST>/httpAuth/app/rest/builds/id:<BUILD_ID> URL I can grab ENV variables via propertys attr, but cant access ENV variables injected via:
'##teamcity[setParameter name='env.<VARIABLE>' value='<VALUE>']' in one of build steps.

Thanks in advance.