How to set culture of popup calendar control in .NET code-behind

I’m trying to set culture of eWorld popup calendar control to current user culture or “ar-LY” in .NET code-behind, However, I got the wrong value of Month when using property of (SelectedDate.Month), so it seems there’s an issue when setting it from code-behind whereas it works well when modifying (Default.aspx) by adding Tag (Culture=“ar-LY”) to ew:calendarpopup, but I lose it when saving from built-in Form Designer.

Any idea to sort out such an issue ?