If you need to make a custom item card (as you are saying builder lacks an item card appropriate for the artifact) I would suggest Power2ool
Power2ool is a free, Flash based website that lets you create item and power cards just like the ones generated by the character builder. It color codes and formats the cards based off using keywords like, "Effect:" and "Hit:" and in the few instances where it doesn't know what to do automatically, can be tricked into formatting correctly.
Even more importantly, Power2ool arranges the power and item cards in order as if they were being printed out for a character sheet from the 4e Character Builder and has built in functionality to print these out on sheets of paper (or into adobe PDFs).
If you decide to use it, message me in chat for help as some of the syntax is finicky.