It's very simple to do these days thanks to our good friend wowhead.com.
1) Search for the item you want to fake link
2) Click the "Link" button at the top right hand corner.
3) Copy the script it gives you into a note pad document.
4) Go to
EnchantId - WoWWiki - Your guide to the World of Warcraft and find the enchant you want. Copy the number to the left of it.
5) Replace the second zero in the long script that wowhead gave you with the enchant id. I used mongoose for this example.
6) Copy and paste into game.