IF you used the ESPP step by step interview THEN you did pass through a page titled "Your Employee Stock Plan Results" and that's where you indicated that the compensation was reported on your W-2.
You can get there again but you can't do so by simply trying to edit your original input and then stopping when you're done. In order to get back to that page you need to get to the very end of the "Stocks, Mutual Funds, Bonds, Other" interview, not simply stop when you've finished entering or editing 1099-B information.
So start the "Stocks, Mutual Funds, Bonds, Other" interview, select Edit next to the brokers name on the page "Here's the investment sales info we have so far", select the sale to Edit and work through that interview - no need to change anything - and keep going in the interview pressing the Done button repeatedly. That will take you back to the "Your Employee Stock Plan Results"page.
Tom Young