Mail routing problem with server name

All linux admins,

We are is using Domino-on-Linux for several years now with great success.

We now installed a Cluster with a second Domino-on-Linux server. Both machines were installed from scratch (to Domino data has been copied to the newly installed CentOS5 servers).

We are facing a big problem :

The server names are notes01/Company and notes02/Company

We cannot send mails from notes01 to notes02 because of following error : Cannot find path to NOTES02/COMPANY (in capitals)

DNS, hosts, Notes connection documents all use small characters.

Where does it come from and how can I explain Domino to send it anyway ???

This problem does not occur in the other direction.

Anyone an idea ?

Alexandre