lookto without changing current fov (donecall needed)

Hello

I tried different ways to keep fov unchanged without success:

lookto(toH,toV,null,linear(10),false,true,mydonecall());
lookto(toH,toV,,linear(10),false,true,mydonecall());

The thing is I really need the donecall so I cannot use just use moveto.

When I mean "keep fov unchanged", I actually leave the possibility to the user to change the fov during the lookto movement...