[Avodah] heter mechira produce

[Shoshana L. Boublil]

During a discussion on another list, someone raised the opinion that 
(according to him) Chareidim consider eating "Heter Mechira" produce like 
eating Tereifot and Neveilot.

I can't figure this one out.

When I asked a Rabbi from Machon HaTorah VeHaretz, he gave me source from 
Chazon Ish and Rav Shlomo Zalman Auerbach that say that Heter Mechira 
produce BeDi'avad are mutar.

I also recall a lecture many years ago, in which the basic issue with regard 
to Heter Mechira was whether or not Shmitta was D'Oraita or DeRabanan in our 
times.  Besides the question of Yovel, the issue was whether the Medina is a 
Malchut, in a halachic sense, which would, if the answer was positive, 
influence the balance of matter so that shmitta would be D'Oraita.

And yet, AFAIK, the majority consider Shmitta in our time D'Rabbanan.

I realize that politics influences things -- but I want to know from a 
straight halachic view.

Comments?

Shoshana L. Boublil