Ramon, I don't know what TIS or Bentley say about the procedure, but it's important to slot the handle into the pull rod before dropping the rod into the tube. Unless there's something physically in the way (dirt?), there shouldn't be anything to prevent the rod from dropping onto the detents of the shifter. However, the button will stay up in the shift handle if the pin in it isn't slotted into the rod.
best, whit