The question is not unique to the EZUIRT. PRIOR to linking a responder device (SwitchLinc in this case) to the controller device (EZUIRT in this case), set the desired Bright level and ramp rate at the SwitchLinc itself. Then link the SwitchLinc to the EZUIRT. The bright level and ramp rate are stored in the Responder to link record that is written in the SwitchLinc link database when the link is established. When the SwitchLinc receives the Group command to turn ON, the SwitchLinc searches its link database looking for a matching Responder to link record. When a matching Responder to link record is found the bright level and ramp rate stored in that link record are used to set the bright level of the SwitchLinc and the stored ramp rate sets the speed at which the bright level is achieved.
As an alternative, if you have a PC, and a PLC (not PLM) or an EZBridge/EZSrve for a powerline interface, you can use the free download software, SimpleHomeNet Utility Suite to Display the existing link records in the SwitchLinc. Once the correct Responder to link record is identified, it can be rewritten with new Bright level (LD1 value of 0xFF is full bright) and new ramp rate (LD2 value of 0X1F is 0.1 second ramp rate) data.