Building hyperlinks using variables/js

Hi all. I want to build a custom hyperlink within Storyline, using data collected from the LMS (SCORM2004 3rd ed). 

First, I need to extract the user ID from the LMS, which my LMS suppliers say can be achieved using the cmi.core.learner_id call. Can Storyline pull this data? How?

Second, I need to insert this user ID into a URL, thus customising the URL to include that user's unique ID. Again, can I do this in Storyline and how?

Third, I need to add a trigger to a button in Storyline that opens this URL in another browser window. How do I pull that URL (which is probably part of a variable) to utilize it in a trigger?

As this is going to cost me money for the LMS suppliers to populate the cmi.core.learner_id field and make other changes, I'd like to know for sure whether Storyline can indeed carry out the functions we need, be it with triggers, variables or Javascript. 

Thanks in advance.