The reference to SSO's power to redeem after Mar 5th, 2013 appears in quarterly and annual financial reports on the SSO website. The full news releases regarding the new 250 million dollar notes issue appear there as well, including reference to a 30 day option to new noteholders to purchase an additional 37.5 million dollars worth of new notes. 

They have also issued notice to noteholders who wish to voluntarily convert old notes (not likely at 43.33!) or redeem for cash by Mar 1st.

Also dbeaude's post of 2/5 11:19 mentions an email from IR where they say they will use funds from the new notes to redeem old ones in early March. Presumably all the old notes unredeemed by Mar 1st will be called in after Mar 5.

What I mean by 'the only benefit' for new noteholders is that the shares convert at a lower rate. Obviously, receiving lower interest on the new notes is not a benefit for existing noteholders that roll their cash from the old notes into the new ones.