Re "radical": I don't think my definition is restrictive, to the contrary, I think some cricles use it too loosely.

Regarding the Republikaner, even the present-day party demands the abolition of the right for asylum (even church asylum, which is rather strange for a party speaking about a superior "Christian-Occidental culture"), which I'd consider a rather radical change. They also demand the abolition of the Verfassungsschutz [Office for the Protection of the Constitution, created to monitor groups suspected of an intent to overthrow the democratic order, like the Nazis did], and the re-creation of Prussia state, which would change Germany rather strongly; and 'total' freedom of speech, which is a transparent sop for Holocaust deniers.

However, the Republikaner that earned the far-right reputation, and the one I am much familiar with, was the time of Franz Schönhuber (until 1994). That was much nastier, they xenophoby was without qualifications, they had no qualms about integrating hardcore ex-Nazis and neo-Nazis, and cooperation with DVU and NPD (the other two, harder far-right parties) foundered only on personalities (who should be the leader). (One small episode from that time I remember fondly was how a Turkish village, upon learning what that nice German gentleman who bought a holiday home does at home, declared Schönhuber an unwelcome person...)

Regarding violence against policemen, I don't know which specific utterance you mean (and thus whether I'd interpret it similarly to you). However, either way, I could surely quote CDU members approving violence by policemen against political demonstrators  -- or worse, deported foreigners. But this is a cultural war of incompatible worldviews that won't lead anywhere. Instead, some deviations:

1. I imagine I would have a hard time explaining how I, personally, think <both> violent protesters and violent policemen can be both right and wrong, and how observers can be wrong about both the the assumption of justified and unjustified violence, by both protesters and policemen; and that without being accused of equivocation. However, to get my perspective across in a different context, I refer you to some of my writing on the Budapest riots in 2006 and 2007 -- where the rioters were on the right and the 'police supporters' on the Right: on the first riot (see the comments), Scary (if you check just one, check this), second major riot, The Day Budapest Burns To Cinder (or not) (third major riot and precedents, with in-person observations).

2. At a level of principles, on the topic of violence against practicioners of the state monopoly on violence, I quote some official documents:

That to secure these rights, Governments are instituted among Men, deriving their just powers from the consent of the governed, That whenever any Form of Government becomes destructive of these ends, it is the Right of the People to alter or to abolish it
(United States Declaration of Independence)

The doctrine of nonresistance against arbitrary power, and oppression, is absurd, slavish, and destructive of the good and happiness of mankind.
(Constitution of New Hampshire)
(Constitution of North Carolina)
(With slight differences, Constitution of Tennessee)