Thanks a lot for your help! It worked. I created a new graphics layer for which I set the weight to zero using IBarrierProperties. I cast the IGraphicsContainer object to the graphicsLayer and add the graphic element to the container.
Since the feature weight is 0, labels that are within the graphic element bounding box are displayed now!
Best,
Johannes
Here comes the code:
Dim pMap As IMap = pMxDoc.FocusMap
Dim graphicsLayer As IGraphicsLayer = New CompositeGraphicsLayerClass()
CType(graphicsLayer, ILayer).Name = "TESTLAYER"
pMap.ActiveGraphicsLayer = CType(graphicsLayer, ILayer)
pMap.AddLayer(CType(graphicsLayer, ILayer))
Dim pBarrierProperties As IBarrierProperties
pBarrierProperties = graphicsLayer
pBarrierProperties.Weight = 0
Dim pGContainer As IGraphicsContainer
pGContainer = pMxDoc.FocusMap
pGContainer = graphicsLayer
pGContainer.AddElement(pGraphicElement1, 0)
pMxDoc.ActiveView.Refresh()