iOS DatePicker binding gives MvxBind:Error for viewmodel => view direction - mvvmcross

Question

I am using an iOS UIDatepicker (weekendOnTimepick) in 'time only'mode in one of my views that needs to update the properties in my Viewmodel whenever the Picker view is changed. The direction Viewmodel => view is only important at View load hence is treated outside of the binding (see code below).
Although this works great (after overcoming the challenges of iOS wrt time localisation), I get a message "MvxBind:Error: 86.61 Problem seen during binding execution for binding Time for TimerOnWeekend - problem ArgumentException: Object type System.DateTime cannot be converted to target type: MonoTouch.Foundation.NSDate"
I guess this has to do with the binding direction I'm not using and doesn't seem to be an issue, but I do fear it will bring some sort of instability to my app.
Question : is this the right way of achieving the goal stated above, or would it be better to for instance ditch binding alltogether and use a View to Viewmodel subscription message with every Datepicker update ?
public override void ViewDidLoad ()
{
base.ViewDidLoad ();
_userSettings = Mvx.Resolve<IHpRepository>().HpFullData.UserSettings;
var set = this.CreateBindingSet<TimerView, TimerViewModel>();
// TODO: check timepicker binding
set.Bind(weekendOnTimepick).For("Time").To(vm => vm.TimerOnWeekend);
int weekendOnHr = _userSettings.TimerOnWeekend / 3600 ;
int weekendOnMin = (_userSettings.TimerOnWeekend % 3600) / 60;
var weekendOnTime = new DateTime (2014, 1, 1, weekendOnHr, weekendOnMin, 0);
var AdjweekendOnTime = weekendOnTime.ToUniversalTime ();
weekendOnTimepick.SetDate (TouchConverter.DateTimeToNSDate(AdjweekendOnTime),true);
set.Apply();
}