This excerpt taken from the PBR 6-K filed Oct 10, 2006.
Enforcement. The Trustee shall enforce the provisions of the Standby Purchase Agreement against Petrobras in accordance with the terms thereof and the terms of the Indenture and Petrobras, by execution of this Fifth Supplemental Indenture, and by so agreeing to become a party to the Indenture, agrees that each Holder of the Notes shall have direct rights under the Standby Purchase Agreement as if it were a party thereto.
Section 3.03. Petrobras hereby (i) acknowledges and agrees to be bound by the provisions of Sections 1.08 and 3.14 of the Indenture and (ii) confirms that (A) its obligations under the Standby Purchase Agreement shall be issued pursuant to the Indenture and (B) it intends for the Holders of the Notes, in addition to those rights under the Standby Purchase Agreement as provided therein, to be entitled to the benefits of the Indenture with respect to their rights against Petrobras under the Standby Purchase Agreement.