Regardless where you live you will manage and control the offshore company in the Seychelles at your own. The company will have a regsitered office address to which you can receive postal mail and packages, if something arrive to you then you will be notified.
If you are the director of the company then you sign docs. like the one you mentioned your self as you would do for any local company where you are the director! It makes no different if it is Offshore company or a local company! If you are not the director but you made use of Nominees then they will sign for you!