[O] using links/org-capture programmatically

[Eric Abrahamsen]

I've got a little sequence I use so often I'd like to automate it, but
am not sure how. Basically it goes:

1. In Gnus, store a link to an email message
2. Call org-capture
3. Choose a template with a REPLY keyword, that gets stored in a certain subtree
4. Pull the last-stored link, to the email message, into the REPLY heading
5. Complete and restore what I had before

If I want to write a single keystroke that does this, how do I insert
the last stored link into the text of the capture template in an elisp
function? Or should I not be using org-capture in a function to begin
with?

Any advice appreciated!

Eric