I tried to add a textbox to form and to get the text from it,it work well in
openwave UP411, for your ref I attach the cs file here.

namespace sdgd
{
public class MobileWebForm1 : System.Web.UI.MobileControls.MobilePage
{
 protected System.Web.UI.MobileControls.Form Form2;
 protected System.Web.UI.MobileControls.TextBox TextBox1;
 protected System.Web.UI.MobileControls.Command Command1;
 protected System.Web.UI.MobileControls.TextBox TextBox2;
 protected System.Web.UI.MobileControls.Link Link1;
 protected System.Web.UI.MobileControls.Form Form1;

 private void Page_Load(object sender, System.EventArgs e)
 {
  // Put user code to initialize the page here
 }

 #region Web Form Designer generated code
 override protected void OnInit(EventArgs e)
 {
  //
  // CODEGEN: This call is required by the ASP.NET Web Form Designer.
  //
  InitializeComponent();
  base.OnInit(e);
 }

   private void InitializeComponent()
 {
  this.Command1.Click += new System.EventHandler(this.Command1_Click);
  this.Load += new System.EventHandler(this.Page_Load);

 }
 #endregion

 private void Command1_Click(object sender, System.EventArgs e)
 {
  this.ActiveForm=Form2;
  TextBox2.Text="form2: " + TextBox1.Text;
 }
}
}

Maybe you can try with UP411.Any problem please ask me free.

Regards
Diamond