Sif do a flux specifically for Silver solder (I have a tub on the shelf from a job I did some time ago) wouldn’t have thought they would make another if the brazing flux would do. But there again you might get away with it.
RonA
I'd be guessing that if it a brazing flux it may have a working temperature of 800C upwards, so unless its a high temperature silver solder it wont work. easyflo silver solder has a working temperature of 550 to 800C.