Routing issue with the word "internet" in the address

[plaval31]

We are running Domino servers v5.0.9a.
For one of our users, in her person document, we have created a secondary internet address in the Short name/UserID field.
This address is "domaine.internet@ourdomain.com"
When someone from the outside world tries to send a mail to that address, he receives a delivery failure telling him that "domain@ourdomain.com" is an unknown user...
If we take a look at what happens at the mail relay level, everything is ok. The mail is routed to the first Notes server with the full address. Afterwards, Notes seems to be unable to manage internally that specific address. Is the word "internet" forbiddden in the first part of the address? Are there some ways to bypass the issue without changing that address?
Thanks for your help.

 

[plaval31]

To bypass that issue, we have created a Person document in Domino directory for "domaine internet" and associated to that virtual person the mail box of the destination user.