If you're still on tonight/tomorrow I'll give you a hand. the files for toasts are both 921.
Maybe you'll want to create a separate background image for toasts, in that case open up the 921 style (usually/should be msgres_4005_921.txt) search for
20061 in 8.5 and/or
20852 for 9.0beta1 and replace that with a custom resource eg 59123
remember you'll need to create images for both normal toasts AND alert toasts or one image/style capable of suiting both
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