S/MIME questions: how to set default key?

[Thomas Klausner]

On Mon, Jan 04, 2016 at 02:12:18PM +0100, stebe at mailbox.org wrote:
> So you might set --default-key USER_ID to the one of your new certificate
> (second in your output list) and add it to gpgsm.conf; you might as well
> use --local-users instead. 

I don't understand what 'local-user' wants to signify as a parameter,
but I can confirm that adding

    local-user FI:NG:ER:PR:IN:T2:...

to my .gnupg/gpgsm.conf does indeed work.

Thank you very much!
 Thomas