Inheritance

Does this work for you...

Type projectileinfo
End type
Type Projectile 	
	
	Method update(deltaT:Float)
	
		Print "updating"

	End Method
	
	
	Method setInput(inputData:TList)
	End Method
	

	Method getOutput:TList()
	End Method
	
	
	
	Method Draw()
		Print "drawing"
	End Method
	
	
	Function create:projectile(info:projectileInfo, firerID, targetBase, targetOther, x#, y#, rot#, vx#=0, vy#=0, vrot#=0)
		
	End Function
	
End Type

myproj:projectile = New projectile
myproj.update(0.5)

?
If so, your problem is somewhere else.
<edit> Arrrgh editing while I'm typing.