Or if you want 1.72/1.73 cross-compatibility, you need to use a function snippet like the one in Planetfall.
Thanks T, will use your solution. The snippet is nescessary for OSE as you can assume, for the OSE escorts derived from yours.
And no, I don't give you-know-what for backwards compatibility before 1.73. Reason being that OSE needs at least two commands that are not in Oolite core before 1.73 to work at all ...
It's actually Kak's original solution that he PM'd be ages ago, but I've just got around to using now I've got a working portable trunk install. But it's nothing too complex anyway that any number of variants will pop up in peoples scripting.