Attachmovie targetpath

I’m attaching [phil+“a”] to [“bob”+i] and I can’t seem to be able to alter phil’s properties. Tracing I get undefined.

_root[“bob”+_root.i].attachMovie(_root.train, _root.phil+“a”, _root.i, {_x:_root.hold._x, _y:_root.mover});

_root.phil._alpha =0;

trace([phil+“a”]._alpha);