"Dragon-Informant" Quest

[jahes64]

Hi
I managed to scan my save file with KBScanner and this was the reward table i got for this quest:

Quest Dragon-informant Experience 2000
Quest Dragon-informant Experience 2000
Quest Dragon-informant Experience 2600
Quest Dragon-informant Gold 35500
Quest Dragon-informant Gold 38000
Quest Dragon-informant Gold 38500
Quest Dragon-informant Magic Rune 5
Quest Dragon-informant Might Rune 5
Quest Dragon-informant Scroll Blizzard 1
Quest Dragon-informant Scroll Ice Snake 1
Quest Dragon-informant Scroll Ice Snake 1
Quest Dragon-informant Scroll Justice 1
Quest Dragon-informant Scroll Sonic Boom 1
Quest Dragon-informant Scroll Timelessness 1
Quest Dragon-informant Spirit Rune 5

I have tried every sort of Dragons (Black, Red, Green, Ice) but the reward was the same (Experience 2600, Gold 38500, Scroll Ice Snake 1, Scroll Timelessness 1, Magic Rune 5).

Anyone knows how may i get other rewards, namely Blizzard Scroll (No store seem to sell this scroll)?
Do i need an undead dragon (Which i couldn't find so far)?