(HELP) How to create a familyinstance attach to a surface?

[Anonymous]

Some familyinstance in MEP should be attached to a suface (ei, surface of a duct) during creation. I try the create method "NewFamilyInstance(XYZ, FamilySymbol, XYZ, Element, StructuralType)". But i didn't get the expectiong result (show in the picture).  Dose anyone knows the right method to create this kind of familyinstance? Thanks.

PS: I also dont have any clue how to connect this kind of familyinstance to the host element, for this seams not a connector to connector connections.

[saikat]

Does this help:

http://thebuildingcoder.typepad.com/blog/2012/02/hosting-a-light-fitting-on-a-reference-plane.html

To create a family instance on a host, you can use either of the following two overloads of NewFamilyInstance():

NewFamilyInstance(XYZ, FamilySymbol, Element, Level, StructuralType)
NewFamilyInstance(XYZ, FamilySymbol, XYZ, Element, StructuralType)

cheers