Hi Shereen

Personally, I've never really taken much notice of any specification in recipes of salted/unsalted butter, I just use whatever I have.  I don't know that it matters a great deal (although presumably whoever writes the recipe thinks it does!) - I guess you'd have to try the finished results made with both types to see whether it does actually taste any different.  Go for it, I'd say (go on, blame it on me if it doesn't taste right ). 

I usually don't worry about whether to use salted or unsalted, but I DID have one disaster when I used salted to make grapefruit curd, it was disgusting, the saltreally ruined it.