Removing small white corner triangles from a rounded logo

[bwood]

This one has me stumped. A client wanted this logo to place on a picture on a calendar. As you can see, there is little white triangles on the corners. This originates from the original company logo - and they wanted me to take the white corners off.
I've tried a lot of things. First I cropped leaving the black border - then I rounded the border. Didn't do it. The crop as transparent. I've tried everything in my knowledge tool kit, but I work with png, and also white background documents that I never had to worry about it.

I'm just about ready to use a brush or some kind of a trace element.

As its time sensitive, I've missed my deadline - but - how would the pros on the board do it. Many thanks,


-Bill