HamP
JAR-OPS 1.405
Where no outer marker or equivalent
position exists, the commander or the pilot to whom
conduct of the flight has been delegated shall make
the decision to continue or abandon the approach
before descending below 1 000 ft above the
aerodrome
In any case I found the answer I was looking for
JAR-OPS 1.192 Terminology
Equivalent Position: a position that
can be established by means of a DME distance, a
suitably located NDB or VOR, SRE or PAR fix or
any other suitable fix between 3 and 5 miles from
threshold that independently establishes the
position of the aeroplane.