Extending LDAP Schema - Problem with OID

I’m trying to extend the LDAP Schema to include an AbbreviatedName so that I can integrate Notes IM with Sametime using LDAP.

I’ve cerated all the fields, however I may be stuck at doing the LDAP Schema.

The problem is the OID. Some documentation suggested using OID id-at-DominoAbbreviatedName, however this does not work, since the Schema.nsf does not allow me to input this.

Is it just a case of looking through the OIDs and using the next available number, or is there a methodology for when using OIDs?

Thanks in advance