First of all what version of MDT Papyrus are you using?
In the 0.8.X all those features are avaiables. In the 0.9.x we are currently working to backport it. It should be available at the end of the month.
Sorry, I've Confused, my problem is with the element "interruptible activity region", no is with sequence node.
I using papyrus 0.9.0_RC3 with eclipse juno, then i think that my problem will be so you say, right?