Can you do fusion in Dragon Ball Z budokai tenkaichi 2

Yes, you must have at least 3 blast stocks and the right characters (i.e. Goten and Trunks) Then you press L2 L3(Left Analog stick) R3(Right Analog stick)
Gotenks = 3 Blast Stocks
Super Gotenks = 4 Blast Stocks
Super Saiyan 3 Gotenks = 5 Blast Stocks
Super Gogeta = 5 Blast Stocks