A number of acharonim say no based on the following.
The Gemara in Shabbos has the following story. There is an issur d'rabbanan to go on a boat on Shabbos. One of the chachamim wanted to get across the river on Shabbos but he didn't want to violate the issur. Therefore he did the following. He got on the boat well before it left and pretended to fall asleep. Then when the boat got to the other side he pretended to wake up and got off. Someone asked his Rebbe how is that permitted? The Rebbe answered that a הערמה is permitted for a talmid chacham to get around an issur d'rabbanan.
These acharonim say that selling your chametz is a הערמה and therefore should only be permitted for chametz d'rabbanan as the Gemara in Shabbos seems to say.
RHS explained why many permit selling real chametz as follows. The Gemara in בכורות says that R' Mari was punished for selling his בכור to a גוי. Yet, Tosafos says that today we do this all the time. Tosafos explains that we have no other choice to save us from the איסור of בכור and therefore it is permitted to do a איסור דאורייתא and sell it to a גוי. You see clearly from the Tosafos and the Gemara in בכורות that a הערמה is permitted even by an issur torah (בכור).
The answer is that הערמה is only prohibited to get you out of doing a mitzva but to save you from violating an aveira a הערמה is always permitted.
What about the Gemara in Shabbos? That is a different case. There the chacham actually violated the issur, he went on the boat on Shabbos. In that situation, he was only allowed to violate an issur d'rabbanan בהערמה.
There is a fundamental distinction. If you are doing the הערמה to prevent you from violating an issur it is always מותר even for an איסור דאורייתא. However, if you are actually violating the issur בהערמה then it is only מותר for an issur d'rabbanan and a talmid chacham.
Since selling real chametz is a הערמה to prevent you from violating the issur it is permitted even for an איסור דאורייתא.