Hey CLK I hope this helps ya, When you go to edit your sig box, instead of the long Ebay link, you can put whatever you like, Ie; CLK's Auctions or My stuff for sale something along those lines
Highlight the word(s) you want to link as what you put in then, Click this button:
A new little box will show up, Paste your link into the box (while making sure your text is still selected)
Then Click 'OK' Then go to the bottom and click save Signature, and you should be set.