I heard it was possible to use HP mini-GBIC modules with Cisco switches, but there is a special command for it.. Has anybody heard anything about it?
Cisco has indicated they do not support the installation of non-Cisco transceiver modules within their equipment. They have a unique identifier code stored in the transceiver's memory that is checked by the software during bootup.
As with anything, people work had to get around the systems. Just remember that if you upgrade the switches software in the future, the hack may no longer work and a new hack will need to be worked.