working version of this code... http://www.softimageblog.com/archives/209

setupDorito()

#imports
import win32com.client
from win32com.client import constants
from win32com.client import Dispatch
 
#globals
xsi	= Dispatch( "XSI.Application" ).Application
xsiPrint = xsi.LogMessage
 
def setupDorito():
	if xsi.Selection < 1:
		xsiPrint("Select an component!",constants.siError)
		return False
 
	root = xsi.ActiveSceneRoot
 
	#create cluster constrained null, setup its look
	clsCnsNull = root.AddNull("clsCnsNull")
	clsCnsNull.primary_icon.value = 0
	clsCnsNull.size.value = 0.1
	clsCnsNull.shadow_icon.value = 7
	clsCnsNull.shadow_colour_custom.value = 1
	clsCnsNull.B.value = 1
	clsCnsNull.G.value = 0.5
 
	#make cluster from selection
	subComponent = xsi.Selection(0).SubComponent
	cnsCls = subComponent.CreateCluster("cnsCls")
 
	#constrain object to cluster
	cns = Dispatch(clsCnsNull.Kinematics.AddConstraint("ObjectToCluster",cnsCls))
	cns.tangent.value = 1
	cns.dirx.value = 0
	cns.diry.value = -1
	cns.upvct_active.value = 1
	cns.upx.value = 1
	cns.upy.value = 0
 
	#make dorito
	dorito = root.AddNull("dorito")
	dorito.primary_icon.value = 0
	dorito.size.value = 0.2
	dorito.shadow_icon.value = 8
	dorito.shadow_colour_custom.value = 1
	dorito.G.value = 1
	dorito.shadow_offsetX.value = 0.1
	dorito.shadow_scaleX.value = 0
 
	clsCnsNull.AddChild(dorito)
	dorito.kinematics.local.transform = XSIMath.CreateTransform()
 
setupDorito()