Scroll API with SearchTemplateRequest

There doesn't seem to be a way to use the scroll api with SearchTemplateRequest() from the Java high level client.

Is this a feature request, or a bug/miss?

I use moustache to expand complex json queries. So I could do a simulate with the SearchTemplateRequest(), and extract the search request json in the searchTemplateResponse, via:
BytesReference bytes=searchTemplateResponse.getSource();
And then use the json to build a standard SearchRequest with scroll.

The issue with this method is that I don't know how to use the Java high level client to submit a pure json based search request. (I tried WrapperQueryBuilder() - but it failed).

I can't find any samples in the docs to do this either.