Found it. It's called "Boy
Meets Tekong: NS Guidebook for
Muslims", issued by Perdaus & MUIS in 2000. Try contacting them
for a copy.
The middle half of the booklet is subtitled "Islam for the Ops
Ready", preaching a pre-prayer checklist (timetable, $1 compass,
water bottle, poncho, etc.), how to perform ablution, how to pray
fast (proper technique & focus) & pray "smart" (combination
prayers, etc.), plus clarification on fasting during Ramadhan as
well as halal/haram food. All within practical context, or army
style - so to speak.
I didn't answer you directly prior cuz I thought maybe the SAF has
a new directive but, from the gist of the fairly-recently
publication, I don't think things have changed much since my time
in the '80s. In other words, the military respects your religious
obligations but won't go out of its way to overaccomodate
them.
Instead, the booklet encourages Muslims to be disciplined &
faithful (when not enough time, water is scarce, too tired, dirty
uniforms/terrain, missed prayers, etc.). At the same time, it
advises that the seeking of permission to pray must be tactful, in
order not to interrupt training or cause inconvenience to
others.