New Post: R.NET - using external libraries (like "signal" or other)

Hello. I tried to write a little program using R.NET 1.5, but have a trouble - have a ParseException on the following code:
GenericVector vec = engine.Evaluate("bf <- butter(5, 0.1)").AsList();

I think, It's connected with a requirement of library including, but have no idea how to implement this.
Pls, help me...