Hi jenng,
I ended up using a paid preparer. She included the Form 8978 amount on 1040 line 12a, Tax. She checked box 3 on that line and indicated that the tax included the 8978 amount.
She also attached a copy of the "Qualified Dividends and Capital Gain Tax Worksheet" that gave every detail of how the line 12a amount was calculated.
Good luck! Like so many things IRS-related, this was to me an unnecessarily confusing exercise.
