Step 1: In your Webmail account, go to your Settings folder and select Compose. Then,create your webmail signature with interactive links in the compose window and save the changes.

Tip: Make those links as user-friendly as possible. Luckily my Doteasy webmail GUI lets me include tooltips in a link. That way people will have some idea of what they are going to see when they click the link.
Step 2: Go to your webmail mailbox and send a message to your Gmail account with that new signature.
Step 3: Go to your Gmail account and open up the message you just sent and give it a test drive.
Step 4: Now you can keep that message handy and copy and paste your signature from there when you want to include it in a Gmail message. When you want to include that signature, simply view that message with your signature, highlight the signature and then copy and paste it into the new message.
Please Note: This only works if you launch Gmail in its own window. (top left corner of inbox window;”Launch Full Gmail”)
Easy!