In portuguese we say letter by letter, some with the english pronounce, mostly with portuguese pronounceI've sometimes wondered how non-English speakers pronounce the names of the various three-letter agencies. It would make sense to me that they pronounce the letters as they would in their own language. Similarly, should I pronounce "CMAS" as a Frenchman would? I'm not sure there's any alternative.
G U E
T D I
S S I
IANTD
Etc
With exception of PADI