V'Haarev Na

I noticed in the weekly summary that the CBJ Halacha Program is currently dealing with the halachos of Birchas HaTorah. It mentions there the malchokes about saying "V'haarev na" with or without a "vav" and whether or not to answer "amen". Seemingly, the two should go together. If one holds that v'haarev is a continuation of the first berachah, then one should not answer amen and the nusach should be "haarev na" without a "vav". If we hold that v'haarev is its own berachah then we would say amen to the first berachah but then the next berachah shouldn't begin with the a "vav" (normally used to connect one thing to the next).

In the Radviller siddur there is a note between the berachah of "la'asok b'divrei Torah" and "v'haarev na" as follows:

So, we see that al pi kabbalah and according to the nusach of Tefila Yeshara that even though one should answer "amen" after the first beracha of Birchas HaTorah ("because it is a its own berachah, in and of itself"), still the nusach is "v'haarev na" with a "vav".