Yes i tried i try to compile the example code:

USBCDC but can't get it work, i want to use a PIC2455.

This is the PBP code:

' USB sample program for PIC18F4550 CDC serial port emulation

' Compilation of this program requires that specific support files be
' available in the source directory. You may also need to modify the
' file USBDESC.ASM so that the proper descriptor files are included. For
' detailed information, see the file PBP\USB18\USB.TXT.

buffer Var Byte[16]
cnt Var Byte

LED Var PORTB.0


Define OSC 48


USBInit
Low LED ' LED off

' Wait for USB input
idleloop:
USBService ' Must service USB regularly
cnt = 16 ' Specify input buffer size
USBIn 3, buffer, cnt, idleloop

' Message received
Toggle LED

buffer[0] = "H"
buffer[1] = "e"
buffer[2] = "l"
buffer[3] = "l"
buffer[4] = "o"
buffer[5] = " "
buffer[6] = "W"
buffer[7] = "o"
buffer[8] = "r"
buffer[9] = "l"
buffer[10] = "d"
buffer[11] = 13
buffer[12] = 10
buffer[13] = 0

outloop:
USBService ' Must service USB regularly
USBOut 3, buffer, 14, outloop

Goto idleloop ' Wait for next buffer