Search FW of nuvi 255W and found only this providers:

TMC Traffic information services: France-Via Michelin, Altech Netstar (ZA), Antenne Bayern (DE), Antenne Niedersachsen (DE), Antenne Thuringen (DE), RTL-ACL (LU), Be Mobile (NL), Total Traffic Network (US, CAN), DLF TMC (DE), FFH (DE), Hit 1 (DE), HITRadio (DE), HR (DE), Infoblu (IT), ITIS (UK), MDR (DE), Nediamobile Nordic (FI,NO,SE,PL), Navteq Traffic (US,CAN), NDR (DE), RBB Berin (DE), RBB Brandenburg (DE), SR (DE), Suna (AUS), SWR (DE), TMC BDR (DE), Navteq traffic (DE), TMobilis (BE), Traffic Master (UK), DIS-Trafficnav (GR), TrafficNav (HU), TrafficNav (IE), Radio Sl/Trafficnav (SI), VIA-Michelin (FR), V-Traffic (FR), WDR (DE).

Nowhere can't found Brazil (BR), maybe this is reason why TMC won't work in Brazil.
Maybe if you write to Garmin and ask why is not Brazil traffic in nuvi 255W FW and if they can add it.