PA34 pilot reports being initially cleared via the EMOLA 4E departure from TFFF. After taxi the instructions are changed to 'right turn direct EMOLA climb to 7;000 FT.' A right turn is initiated at 1;000 FT and the pilot is later advised that he should have turned at 2;000 FT; as the early turn activated a terrain warning.

Narrative

When I received my clearance I was given the EMOLA 4E and I had read the departure and programmed the GPS. It was clear I had to fly up to 2;000 FT on a 098 from FOF; then turn right and inbound on [the FOF 142 radial] to FOF; passing FOF; I had to follow 326 [radial] of FOF. I was given 7;000 FT. After taxi though; Tower called and changed my clearance. After departure turn right direct EMOLA. [They] gave me 7;000 FT as climb restriction and the QNE 1013. I thought this meant no restriction on takeoff altitude in the turn. I climbed through 1;000 then turned right on course. Tower advised me to go to Lamentin Control. Lamentin gave me a 270 degree vector. A few minutes later the Controller called me asking if I had read the departure procedures. He said I had triggered the low altitude alerter; that all departures had to turn only after 2;000 FT. I explained that I had indeed but Tower had given me instructions to turn right; I assumed no altitude turn restriction. He said; ok I understand; no problem you did turn right not left. I learned that next time I am given a change from a standard departure procedure I will question the altitude restrictions according to the departure procedure.