[NTG-context] Problem with letter module

Hi, I am writing a letter with the 'letter' module (mkiv and last beta) and the \encl{} command doesn't work anymore. I know that the module has been rewriten recently but I can't find any doc or examples of the new syntax. I tried to look at the source code but it doesn't help. So is there any command which replace \encl{}? And is there any documentation (even succint) of the new module? Thanks. -- Romain Diss