How we can access Content Place Holder from Intersoft Webpane Manager

• I created Master page in asp.net and define content place holder in Intersoft WebpaneManager.
• I also created default.aspx page and implement master page. In default.aspx, I defined label Control in asp:content control.
• In page load of default.aspx, I tried to assign any text to label control then it show run time Exception "object reference is not set".
• I searched and find that intersoft webpane Manager limited the scope of content place holder because content placeholder can be accessed easily if It is defined outside of WebpaneManager.

So how we can access the content place holder in Webpane Manager

Any one help me