How to pass and use web page to an external class?

Given: (I am new to web programming)
 
1. Visual Studio 2013, C# / VB
 
2. I have a front end C# Web app that handles the UI.
 
3. The C# page code behind calls a vb class in an external DLL to do the business logic.
 
4. The VB business class needs to update info on the UI page with status, etc. as it is running so it needs access to the Page.
 
How do you pass the page to the VB constructor?
 
I have tried various options as:
 
C#

VBMain VBM;
VBM = New VBMain(this);

with
 
VB
VBMain ...
Sub New(pWebCtl as Object)
.

Dim MyLblMsg as System.Web.UI.WebControls.Label = pWebCtl.FindControl("lblMsg")

 
but MyLblMsg is always nothing.
 
How do you pass and use the web page?
 
If I pass the label itself I do get it but would need an UpdatePanel to have it update. (This would be put in once I get the basics working).
 

How to pass and use web page to an external class?