forget doing sth

[joham]

Can we say
I forgot meeting him before.
I remember to have met him before. ??

A.J. Thomson & A.V. Martinet say in their A PRACTICAL ENGLISH GRAMMAR that we don't use forget doing sth in an affirmative sentence. Is that so? And can remember followed by to have done sth?

Thank you.

[Tdol]

It's possible to use the affirmative. I wouldn't use 'remember to have met'