Have a look at ManageTabs.ascx.vb:
Dim objTabs As New TabController
Dim objTab As New TabInfo
objTab.TabID = TabId
objTab.PortalID = PortalId
objTab.TabName = txtTabName.Text
objTab.Title = txtTitle.Text
objTab.Description = txtDescription.Text
objTab.KeyWords = txtKeyWords.Text
objTab.IsVisible = (Not chkHidden.Checked)
objTab.DisableLink = chkDisableLink.Checked
objTab.ParentId = Int32.Parse(cboTab.SelectedItem.Value)
objTab.IconFile = strIcon
objTab.IsDeleted = False
objTab.Url = ctlURL.Url
objTab.TabPermissions = dgPermissions.Permissions
objTab.SkinSrc = ctlSkin.SkinSrc
objTab.ContainerSrc = ctlContainer.SkinSrc
objTab.TabPath = GenerateTabPath(objTab.ParentId, objTab.TabName)
If txtStartDate.Text <> "" Then
objTab.StartDate = Convert.ToDateTime(txtStartDate.Text)
Else
objTab.StartDate = Null.NullDate
End If
If txtEndDate.Text <> "" Then
objTab.EndDate = Convert.ToDateTime(txtEndDate.Text)
Else
objTab.EndDate = Null.NullDate
End If
If txtRefreshInterval.Text.Length > 0 AndAlso IsNumeric(txtRefreshInterval.Text) Then
objTab.RefreshInterval = Convert.ToInt32(txtRefreshInterval.Text)
End If
objTab.PageHeadText = txtPageHeadText.Text
objTab.TabID = objTabs.AddTab(objTab)