Replacing boost with std implementation

What is the correct way to replace this:

std::ostringstream buf;
std::for_each(bd.begin(), bd.end(), buf << boost::lambda::constant("&nbsp;") << boost::lambda::_1);

With an implementation that doesn't use boost? This is what I've tried:

std::string backspace("&nbps;");
std::ostringstream buf;        
std::for_each(bd.begin(), bd.end(), buf << backspace << std::placeholders::_1);

The second '<<' is underlined in red and I get the error message:

error C2679: binary '<<' : no operator found which takes a right-hand operand of type 'std::_Ph<1>' (or there is no acceptable conversion)