To make it clear, ACAPI_Element_Select is working with neig points of elements.
If you have element GUIDs it's not a problem, because you can convert it to neig points the following way:
- with the GUID get the element's header using ACAPI_Element_GetHeader
- use ElemHead_To_Neig function (can be found in APICommon.h in example AddOns) to convert the elemhead to neig