Hi Jane,
We do have a few people who are on an insulin and Byetta combination. Have a look at the thread "Anyone Use Byetta" in the Diabetes Discussions section. Because Byetta encourages your pancreas to produce insulin, and at an appropriate amount for what you have eaten, you should need a much lower dose of insulin than you have been taking in order to avoid an over-supply of insulin and resultant hypos. What seems to be the normal approach is to reduce the insulin initially by between a half and a third. But you will need to test at every meal in order to get the balance right.