Sign key and export for each UID

[atair]

Hi all,

I'm now in the situation to sign one other's key for the first time.
He signed mine some days ago and sent me an email "Your PGP key
<keyid>" to each UID of my key with an attached file
"<my-keyid>.<index of UID>.signed-by-<his-keyid>.asc".
I know that I can use --sign to sign the key and then --export to
export it, but I don't know how to do this for each UID (content of
attached files differ). I also discovered, that there's a sign, lsign,
... in the interactive mode with --edit-key -- what are they for/how
do they differ from normal --sign?

To me, this seems like a standard procedure/template, is it? Where to get it?
To me this looks pretty good, as it respects the signed person's
freedom to publish the signature on the keyservers he/she wants to
(and not me doing sth. with one others key).

Thanks!