Thank you Princy.
What I did was simply specify "Vista" skin for the radWindowManager:
<
telerik:RadWindowManager
ID="RadWindowManager1" runat="server" AutoSize="True" DestroyOnClose="True" EnableShadow="true" Skin="Vista">
and call the radAlert from code as follows:
RadWindowManager1.RadAlert(
"RadAlert style test", 330, 100, "Title", "")
The "Vista" skin was correctly applied to radAlert.
Regards,
M.R.