Yes it is possible. You can just use it in a session as part of a trade plan. You need to find out if the System calls the SetTradeRisk function. If yes then you can run a percent risk plan. If not you need to call the System from a rapper which sets the SetTradeRisk Function
Sub BlackBoxCall(SLen,LLen,DollarStop)
BlackBoxSystem(SLen,LLen)
SetTradeRisk(DollarStop/BigPointValue)
End Function