Passing a Variable into an eval() statement

[CES]

All,
I was wondering is their a way of passing a variable into an eval()
statement? I've created a custom eval() dll to use with my VB.net code.
Every thing works fine until I try to pass a variable into the text string .
In the code below I'm trying to pass the variable zz into txtFS which comes
from the file file.txt. Any suggestions on how to get this to work would be
appreciated.
CES
dim _file As String = "file.txt"
dim myFileStream As New FileStream(includesPath &
_file,FileMode.Open,FileAccess.Read)
dim sr As StreamReader = new StreamReader(myFileStream)
dim txtFS As String = sr.ReadToEnd()
dim x As New jsEval()
dim zz As String = "This is the text I want to pass into the..."
txtFS = x.eval(txtFS)

-----------------file.txt-----------------------------
var now = new Date();

var footer = zz + "<p class=\"footer\">Copyright © " + now.getYear() + " -
All rights reserved.<br />";
footer = footer + "Use of this site signifies the users complete agreement
to all terms,<br />";
footer = footer + "as described within the Terms of Use page ( Updated
10/10/2003 ).</p>";