I have just received a Schengen visa issued by Germany for a visit from 25-30 July 2013. The visa is for multiple entry. I am also visiting Belgium from 06-09 August but, although I requested the Schengen visa to be valid until 09 August, the German consulate in Cape Town issued the visa only for the dates I will be in Germany. Can I go to Belgium with this visa or must I apply to the Belgian authorities?
I'm afraid that you will need another visa for Belgium. Since your visa is only valid until end of July, you will not be able to enter Belgium in August with the same visa.