I had the exact same problem two weeks ago. Just remember the law specifies that you have to record your hours in some permanent form and supply them, upon request, within a reasonable timeframe, to the authorities. The law does specify WHAT you need to record, but not HOW to record it.
My logbook is the Jeppesen Professional one (only one that was available at the flight school I trained). It has columns for SE, ME and two blank columns behind that. I simply used these for Glider and TMG, respectively. I also added the flight time to the total time column and since I was training with an instructor on board, used the "dual" column. Had the instructor sign. No problem.
So as far as my logbook is concerned, Glider and TMG are just different class ratings.
Gliding is great fun. Hope you enjoy the course.