How to store base64 string as binary?

Hi all cloud developers,

currently I'm facing issue to which I can't find solution. I get through web service call binary content as base64 string. I want to store it as attachment in cloud. But currently seems like there is no possibility to do that.

First I thought that Binary.ParseFromString() function could solve this issue but now I understood that it's used differently.

Does anybody of you faced this issue and found solution?

Thanks,
Uldis