rpy2: Convert FloatVector or Matrix back to a Python array or list?

This worked like a charm:

vector=numpy.asarray(vector_R)

Found the answer myself :-). Suppose vector_R is a FloatVector. To convert it back to Python you need to do:

import rpy2.robjects.numpy2ri as rpyn
vector=rpyn.ri2numpy(vector_R)

And that's it! "vector" is now a Numpy array.