Now here is an out of the box idea ; go to the art store and buy some Fimo polymer clay .
Use said clay to form an appropriate gonjo on the keris blade and bake it until hard in the oven; 275 f or so for 10 minutes .
This won't damage the blade .
If you can remove the hardened Fimo gonjo from your keris then you would have a 3D model to send to Madura with no customs problems ... a little imagination, etc ..