Viewstate of ascx lost between postbacks

In my ASP.NET application, I am loading an .ascx dynamically using LoadControl, using the following pattern:

var ctrl = LoadControl("/path/to/control.ascx");
((ControlType)ctrl).SomeProperty = someData;
placeholder.Controls.Add(ctrl);

The control that I add saves the SomeProperty property value directly to ViewState, as follows:

public int? SomeProperty
{
    get { return (int?)ViewState["SomeProperty"]; }
    set { ViewState["SomeProperty"] = value; }
}

After that, the ascx control lives a life on its own and all is well until postback occurs. When the page posts back, suddenly the view state is empty! I suspect this happens because I manipulate the ViewState before I add the instantiated ascx to my page. Also, I can prevent the ViewState from getting lost by adding the following line in the Page_Load() method of my ascx control:

SomeProperty = SomeProperty;

I have to do the above for each and every property to ensure that the ViewState is preserved. Now, is there a prettier way of doing this? Manipulating the ViewState after the instantiated .ascx has been added to the page is not an option – I need the contents of the ViewState in the Page_Init() and Page_Load() methods, which are triggered the instant I add the .ascx to my page.

Thanks.