Thank you all for your comments and suggestions - This is what I did.

After the spanking, I stood Lisa in the corner and she cried for about 1/2 hour. The next day we discussed what had prompter her to do what she had done. She admitted that the shop lifting was based upon a dare from her friend....she admits it was a bad decision on her part, and (after talking to the store manager), she will pay the store the $45 out of her allowance that the sweater would have cost, plus she does not get the sweater. She said that the lie was just her way of getting to do what she wanted - and she has been grouded for 1 week for telling me the lie.
She also said that based upon her 12 years of life, she didn't think there was anything she could do that would result in a spanking, and after receiving one, she does not want to experience another one. So dispite reservations about giving her one, if it works out that she now knows that there are some absoultely unacceptable behaviors, that can result in a spanking I think the situation has a positive outcome.