It is v5.5.3996 R2 version.
I have created a web user control (webpart) with some tabs. one of the tabs shows an altenative form of a custom table. the codes that belongs to this action is:
.ascx page: 
  <cms:CustomTableForm ID="newAdvertise" runat="server"  />  
.ascx.cs page:
 // Get alternative form info for new advertise                       
AlternativeFormInfo afi0 =AlternativeFormInfoProvider.GetAlternativeFormInfo(NewAdvertiseFormName);
 if (afi0 != null)
{
   newAdvertise.ShowPrivateFields = true;
   newAdvertise.CustomTableId = CMS.SettingsProvider.DataClassInfoProvider.GetDataClass("AD.Advertise").ClassID;
   newAdvertise.FormMode = CMS.FormEngine.FormModeEnum.Insert;
   newAdvertise.AlternativeFormFullName = this.NewAdvertiseFormName;
}
else
{
   lblError.Text = String.Format(ResHelper.GetString("altform.formdoesntexists"), NewAdvertiseFormName);
   lblError.Visible = true;
   newAdvertise.Visible = false;
}
it shows the form correctly and saves data, the only problem is disappearance of WYSIWYG toolbar.