H1b Receipt number in i765?

[Neetha_Vishnu]

Hi,

We are filing my spouse's H1B extension, my H4 extension and i765 concurrently.
It requires me to fill in my spouse's H1b receipt number, since we are filing the extension what should we fill in for the receipt number?
I'm concerned that if I fill in his current receipt number, the EAD issued will be valid only for dates before the extension is approved.

Thanks,
Neetha