i solved this problem too ! i extract the files from SIS file and created a PKG file with this content :
#{"GnuBox"},(0x097764f0),1,0,0
;Localised vendor
%{"Borteh"}
;Non-localised vendor
:"Borteh"
; Product/Platform Compatibility
; 3250 UID
[0x101F7961], 0, 0, 0, {"Series60ProductID"}...