There was some frustration for Poole in organising the meeting, as they were forced to stage their home leg at Wimborne Road on a Tuesday, rather than a Wednesday.
It will take place this coming Tuesday, September 9, with tapes up at 7.30pm.
Redcar finished third in the league table, with Pirates in second after Glasgow finished top.
Pirates promoter Danny Ford explained the change of day for the meeting: “It is not ideal to be staging a playoff semifinal on a Tuesday, but to go on the next available Wednesday would mean waiting until 24th September, which would have been four weeks since our last home fixture.
“We did offer Redcar a Friday night, but that was declined.”
He added: “It is a very frustrating situation because we have done our job and completed our fixtures on time, yet with other BSN and KO Cup ties dragging on, we have been left waiting around.”
There is no set date yet for the second leg.
Pirates other two scheduled meetings at this stage see them travel to Glasgow on Sunday for the second leg of the KO Cup semifinal, with a 14-point lead, before heading to Oxford on Wednesday, September 17, with a 26-point lead.