No, you cannot (at least as far as I know). You can, however, create a simple command-line front-end (an exe) to your DLL and you can invoke that through the scheduler. You can pass various command-line parameters to it to control what actions to perform and how.
You simply need to create a console application project and add a reference to your DLL; you can then call public exported functions from the DLL (or you can use public managed types if it's a managed DLL).