define non linear transistor in cst

hi i have working cst a couple of month about antennas and now i want to design rf circuit like lna power amp. i find circuit plan that include bfp640 transistor and this transistor dont exist in cst library and cst want spice model for non-existent component how can i define a transistor that use spice parameters in cst not use any other program
* i have datasheet that exist spice parameters

Do u find your answer? i have the same problem as you have

Just create a schematic in CST with your design and use "spice import block" to include a spice model file of your transistor.