Disintegrate got reflected when I tested it. You have to fail the save to take damage in order to have it reflect. You don't reflect damage that you don't take, if that makes any sense.
Code:
castspell: cnr96 spl405 (Disintegrate) vis0 x23 y15 spldmg999
vis 0 xvis 0
blastsqr: unr363 x23 y15 aoe0 dmg999 eff2 spc1082151040 as10186 al9
affectvic vic364 hv0
hitunit 363 364 dmg999 spec1082151040 ba2
spec_mr pen 13 mr 18 (unr 363 vic 364 dmg 2 eff 999)
damage shift negated 1007 pnts of dmg
hitunit 364 363 dmg1007 spec128 ba2
damage 1012 on Maker of Heroes, spec0x80 ba2