Actually, this sounds like an Aid...
Let's say you did the Bokken like this:
20 Multipower: 30 point reserve (-1/2 OIF, Bokken of Opportunity)
1u 5d6 Hand-to-Hand-Attack, (-1/2 Mandatory Lim), 0 END for 10 points of HA, (30 Active) END = 1
5u 4d6 HKA, (-1/4 Only while Aided),Armor Piercing, (90 Active) END = 9
And, the Aid looks like this...
100 Aid: 10d6 points to Multipower Reserve
Or, another possibility, with GM approval...
50 Succor: 10d6 points to Multipower Reserve END = 5
note: points remain for as long as END cost is paid, then fade immediately
Does this do what you want...?