It's not the only way this can be translated from Dutch. It can also be read as:
... 2 of your scouts were shot by me, fair and square, below the koppie...
Nowhere is there the phrase "by my order"
spioen can be scout or lookout, as well as spy
juist has a large number of meanings all in the sense of "being above board", like justly, correctly, aptly, etc
verhoek is a typo, should be verzoek