[Pharo-project] Balloon engine and bitmap fills: any clues why it ignores an alpha channel of bitmap?

I tried various paint rules 24, 34 nothing. A balloon engine seems like completely ignores an alpha channel, so i could use it for filling shapes using bitmaps as long as these bitmaps fully opaque. I thought i could use a generic way to render bitmaps, instead of using awkward warpBlt... but it seems like something in plugin discards/ignores an alpha channel of source bitmap. I would be happy if this is not true. -- Best regards, Igor Stasenko AKA sig.