Solution 1:
Use Mech Lab Maid.
Solution 2:
- Customize the mech in mechlab.
- Rename that mech.
- Save
- Go back to the previous mech and click delete.
Hex edit the .mek file in question.
Just look in the hex for the name of the mech and then overwrite it.
Make sure that there is no more than 16 characters.
Solution 4:
Use the mech rename utility that Will Day created.