Is it possible to put a {pu} in there, like {mi du le pu te xatra be do}?
What about indefinite references, though? That is, "I am *a* man who wrote a
letter to you?
If the sex is not important, only the letter-writing, then {mi pu te xatra
be do} works, but if you want to include "man" then you have to bring the
{poi}-ness in somehow. And then {mi du lo nanmu poi pu te xatra be do}
sounds wrong again -- and {mi nanmu gi'e pu te xatra be do} sounds more like
a {noi} connection than a {poi} one to me. Maybe {mi du pa le ro nanmu poi
pu te xatra be do} or something? Not sure whether {du} is correct in such a
case, since I'm not thinking of one letter-writing man in particular, only
stating that I am one such.