Troubles with using a user control

Im using a Top Navigation Bar Web control in my application.
This Bar uses Images. Im trying to dynalically assign the relative URL
path as image path. That is, a particular image can have src attribute
as "../../images" or "images/" etc based on a public property of
control, callingDepth. This property is set in control delaration in
aspx page.
Im using src="http://pics.10026.com/?src=<% #fixRelPath("Images/med_upper_left1.gif") %> function
call in the ASPx pages.
The problem is that this function is not at all called all through page
load.
Any Clue on what i'm missing.
Thanks for Help.Expressions surrounded by <% # and %> are evaluated when the control
is DataBound. So you need to call the DataBind on the object, or a
container of that object.

For more info on DataBinding Expressions, see
http://www.dotnetjunkies.com/quicks...atabinding.aspx