short question concerning usb jump table

Hello,

I am writing a firmware with keil uvision2 which has to use the UART.
Unfortunately, I'm writing the jump table

XXXXX code (ISR_com) 
extrn code (ISR_Sudav, ... , ISR_Ep0in, ... )

; Interrupt Vectors

CSEG AT 23H 
SERIAL_AutoVector equ $ + 2
ljmp SERIAL_Jump_Table 

CSEG AT 43H
USB_AutoVector equ $ + 2
ljmp USB_Jump_Table

where ISR_com is my serial port interrupt.
But I'm unable to find what should be written instead of XXX ! If I'm right, it should be stg like SERIAL PORT !?

Thank you in advance,

stephane