[PD] externals tutorial: link error

I'm getting a link error when following the counter tutorial from the following page:

http://pdstatic.iem.at/externals-HOWTO/node4.html

2>counter.obj : error LNK2001: unresolved external symbol _s_float 2>C:\Users\Elliott...\externals\build\Debug\counter.dll : fatal error LNK1120: 1 unresolved externals

I got the first (hello world) example to build and link and run, so I'm not sure what I'm doing wrong here. I am definitely linking against pd.lib, because if I stop linking against it, I get about 8 link errors instead of

1. My code is identical to the example except for an added extern "C"

and __declspec(dllexport) to get the counter_setup function to have the correct visibility.

I am building with MS Visual Studio 2010 and the Pd 0.42.5 from http://www.crca.ucsd.edu/~msp/software.html .

I would be happy to provide more details on my code and build system if that would be helpful.

Thanks in advance.