Hello Freddy,
when you follow strong to Albert Zonneveld it is a Sewar. Other, like Henk, say that it is a Tumbok Lada. But who I am to give the correct classification. But maybe Albert read this threat and can clear this!? See also this threat:
http://www.vikingsword.com/vb/showthread.php?t=8203
The handle is indeed not original, it's a keris handle from Cirebon. The original handle is maybe long time before broken and the owner give it this handle.
Nice dagger!
sajen