is it possible that i stand behind uke facing his back so that we are facing the same direction? i wanna walk to him then decap. and 500 engage dist

I think player rotation 180 would do it. you would have to turn yourself around though.

also, should be in support.

Why exactly should this be in support?

Use a negative engagedistance to put yourself behind uke and set engagerplayerrot 0,0,180,0,0,0
I think that command isn't working properly but you can enter the command manually in the rpl file though.

Create a new replay file with nothing happening and save it.
Rightclick the replay file, open with texteditor
And paste
ENGAGE 0; 0.000000 -3.000000 0.000000 0 0 180
ENGAGE 1; 0.000000 0.000000 0.000000 0 0 180
between AUTHOR 0 and NEWGAME

You can change the value of -3 to get closer or farther away from Uke.