With simple change from tutorial,
Dim robapp As IRobotApplication
Set robapp = New RobotApplication
' Generate new load case.
Dim cas As IRobotSimpleCase
Set cas = robapp.Project.Structure.Cases.CreateSimple(robapp.Project.Structure.Cases.FreeNumber, _
"Case_1", I_CN_EXPLOATATION, I_CAT_STATIC_LINEAR)
' Define load record types.
cas.Records.New I_LRT_BAR_THERMAL
' Get the first created load record
Dim rec As IRobotLoadRecord
Set rec = cas.Records.Get(1)
'Define the list of objects to which load will be applied.
rec.Objects.FromText "7 8"
' Define the type of thermal load.see robotbarthermalrecordvalues. You have to see if you want diferential temperature gradient in y or Z....
rec.SetValue I_BTRV_TY, 15
' Free previously declared variables.
Set rec = Nothing
Set cas = Nothing
Set robapp = Nothing
Is this ok for you?