You'll probably have to write a Python wrapper for it. You'll find documentation that here http://www.python.org/doc/1.5.2p2/ext/ext.html In general, Poser includes a complete Python runtime that can use extensions like any other 1.5.2 Python environment. If it's a rather popular .dll, ask in the Python mailing lists or comp.lang.python for it, maybe someone already wrote a Python module for it.