Ok here is the problem example with two bo’s
1st I’ll show what works with datasets
NOTE booth business projects referance LockboxLib

HUT Business project
HUTBO.FetchByDLN(dnl as Int)as dataset implements iDataCap.FetchByDLN
STR Business Project
STRBO.FetchByDLN(dnl as Int)as dataset implements iDataCap.FetchByDLN

Up in the LockboxLib project we have the following interface
Interface iDataCap
Function FetchByDLN(dnl as Int)as dataset
End interface
This works. Dataset is common so every project returns it no problem

Here is whats not working

HUT Business project
HUTBO.GetEntityListByDLN(dnl as Int)as mmbindinglist(Of DataCap)implements iDataCap. GetEntityListByDLN
STR Business Project
STRBO.GetEntityList(dnl as Int)as mmbindinglist(Of DataCap)implements iDataCap. GetEntityListByDLN


Interface iDataCap
Function GetEntityListByDLN(dnl as Int)as mmbindinglist(Of AbusinessEntity)
End interface