The DITA Help Subcommittee is discussing a proposal to create a new <help-context> element to hold metadata required for context-sensitive Help. The proposal would see the new element fit under the <topicmeta> element in the ditamap, and/or in the <prolog> element in the topic. The element would hold context numbers and/or context strings, and/or a reference to a window description. (There would need to be a separate element in the ditamap that would store the characteristics of a window named in the context-help element.)

In addition to this approach of storing context hooks in the DITA content, it would still be possible, under an associated proposal, to store context hooks in a separate file externally from the DITA source. How that would work is the next problem to tackle!