[Samba] Samba2.x trusting samba3 domain

[FM]

Hello,
I have a samba 2.x domain.
On another machine I created a samba3 domain (ldap).
I want to migrate my users from samba2 domain to samba3 domain.
It will take some time so I need a trust relationship between domain

Can I establish a bidirectional trust relationship between those domain ?
Using google I found how-to for samba3 but not for samba2.
What is the samba2 equivalent command of :
net rpc trustdom establish

Thanks,
FM