OTA Client: Creating a Function that returns a List of ReqFactory Items

Hello! 

I'm trying to do a macro in excel vba for get the requirements for an specific project.

I need a function that returns a List of ReqFactory objects.

For a given Parent ID requirement I want to get the Child Items. I use the following code for get the first child items and later i'll improve another function to get the list with the items for each Parent ID, but it don't work:

Function List0() As List
'==========================
Dim reqF As ReqFactory
'==========================
Set reqF = tdc.ReqFactory
List0 = reqF.GetChildrenList(0)

End Function

The tdc object is created in another part of the code, so it's not the problem. 

Thanks for your attention.