joining curves

Hello,

 

I drew two curves using the Bezier tool. I am trying to join the two curves by attching one end node of the first curve to an end node of the second curve. This does not work. In the end I would like to do the same with the second end node of the first curve (namely attach it to the second end node of the second curve), so that I obtain a closed curve.

Any help is appreciated.

Thanks,

Adril