Under H1-B portability, what should I do when the Employer wants me to complete the Form I-9, Employment Eligibility Verification?

Though there is no clear directive on the issue, the situation appears to be analogous to the 240-day grace period, which authorizes employment with the same employer for up to 240 days after an extension petition is filed. In both circumstances, the employment is authorized but there is no provision on the I-9 form for the documentation of this fact. Thus, employers may want to follow whatever documentation procedures they use for the 240-day grace period.