Alcatel Lucent SFP+ ports and 1Gb SFPs (mGIBCs)

So how do you get a 1Gb SFP to work come up when it's plugged into a 1Gb/10Gb SFP+ port (on an Alcatel Lucent 6900 in this case)? The port shows the transceiver information (-> show transceivers) correctly but I wasn't getting a "link up".

You have to turn off auto-negotiate on the port in question it seems:

My_AL -> interfaces port 2/1 autoneg disable

My_AL -> show interface 2/1 status
                      DETECTED-VALUES         CONFIGURED-VALUES
 Slot/ Admin  Auto  Speed   Duplex  Pause   Speed   Duplex  Pause  Link
 Port  Status Nego  (Mbps)                  (Mbps)                 Trap
------+------+----+--------+------+-------+--------+------+-------+-----
 2/1      en   dis    1000   Full     -       100    Half     -     dis