Export to GeoTiff fails if product contains only tie-pont

Exporting a product which contains only tie-point grids to GeoTIFF format will fail.
This problem including a possible work around is originally posted in the forum: http://www.brockmann-consult.de/cms/web/beam/forum/-/message_boards/message/61214

This is the exception stack trace logged to the console:
java.lang.IllegalArgumentException: type is not supported
at org.esa.beam.framework.datamodel.ProductData.getElemSize(ProductData.java:352)
at org.esa.beam.dataio.geotiff.internal.TiffIFD.calculateBitsPerSample(TiffIFD.java:419)
at org.esa.beam.dataio.geotiff.internal.TiffIFD.initEntrys(TiffIFD.java:162)
at org.esa.beam.dataio.geotiff.internal.TiffIFD.<init>(TiffIFD.java:59)
at org.esa.beam.dataio.geotiff.internal.TiffHeader.<init>(TiffHeader.java:48)
at org.esa.beam.dataio.geotiff.GeoTiffProductWriter.writeGeoTIFFProduct(GeoTiffProductWriter.java:91)
at org.esa.beam.dataio.geotiff.GeoTiffProductWriter.writeProductNodesImpl(GeoTiffProductWriter.java:81)
at org.esa.beam.framework.dataio.AbstractProductWriter.writeProductNodes(AbstractProductWriter.java:112)
at org.esa.beam.framework.dataio.ProductIO.writeProduct(ProductIO.java:368)
at org.esa.beam.visat.VisatApp.writeProductImpl(VisatApp.java:1565)
at org.esa.beam.visat.VisatApp.access$400(VisatApp.java:154)
at org.esa.beam.visat.VisatApp$5.doInBackground(VisatApp.java:1294)
at javax.swing.SwingWorker$1.call(SwingWorker.java:277)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at javax.swing.SwingWorker.run(SwingWorker.java:316)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)

This happen because the type (maxElemSizeBandDataType) is unknown.
When retrieving the value for this field only bands are considered an no tie-points.
See method initEntrys(final Product product);