Replacing special XML characters in vb.net

I've got a website where a user needs to print details from a customer info screen onto an envelope to be mailed to said customer.

I have an xml template doc that is on the server and a function that pulls info from the customer form and makes strings (name and address strings) and places those into the template. When the button is clicked to generate it opens an instance of MS Word on their local machine and allows them to print the envelope with all the details entered for them.

The only issue now is when you have an address or company name with a "&" in it the function crashes out as the "&" is a special character in XML. What's the best way to compare the string and replace the "&"?   I'll give the code example below:


Public Shared Function CreateEnvelopeForPrint(ByVal LicenceFormParam As LicenceForm, ByVal TemplateStringParam As String) As String

            Dim Addr1 As String = ""
            Dim Addr2 As String = ""
            Dim Addr3 As String = ""
            Dim Addr4 As String = ""
            Dim Addr5 As String = ""

            With LicenceFormParam

                ''Creating the strings to hold the customer's names and addresses
                Dim PrimaryOwner As String = .PrimaryFirstName + " " + .PrimaryLastName
                Dim SecondaryOwner As String = .SecondaryFirstName + " " + .SecondaryLastName

                ' Build line that contains place, province/state and postal code
                Dim PlaceLineStr As String
                If .ProvinceCode.Equals("99") Then
                    PlaceLineStr = .PlaceName + ", " + .CountryName
                Else
                    PlaceLineStr = .PlaceName + " " + .ProvinceCode + "  " + .PostalCode
                End If


                If (.EnterpriseName <> "") Then

                    Addr1 = .EnterpriseName

                    If (.PrimaryLastName <> "") Then

                        Addr2 = PrimaryOwner
                        If (.SecondaryLastName <> "") Then
                            Addr2 = Addr2 + " / " + SecondaryOwner
                        End If

                    Else
                        Addr2 = .AddressLine1
                    End If

                Else

                    Addr1 = PrimaryOwner

                    If (.SecondaryLastName <> "") Then
                        Addr1 = Addr1 + " / " + SecondaryOwner
                    End If

                    Addr2 = .AddressLine1

                End If

                If Addr2 = .AddressLine1 Then

                    If .AddressLine2 <> "" Then
                        Addr3 = .AddressLine2
                        Addr4 = PlaceLineStr
                    Else
                        Addr3 = PlaceLineStr
                    End If

                Else

                    Addr3 = .AddressLine1

                    If .AddressLine2 <> "" Then
                        Addr4 = .AddressLine2
                        Addr5 = PlaceLineStr
                    Else
                        Addr4 = PlaceLineStr
                    End If

                End If

            End With

            'Replace lines $ADDRX$ place holders in template with the appropriate upper case line built above
            TemplateStringParam = TemplateStringParam.Replace("$ADDR1$", Addr1.ToUpper)
            TemplateStringParam = TemplateStringParam.Replace("$ADDR2$", Addr2.ToUpper)
            TemplateStringParam = TemplateStringParam.Replace("$ADDR3$", Addr3.ToUpper)
            TemplateStringParam = TemplateStringParam.Replace("$ADDR4$", Addr4.ToUpper)
            TemplateStringParam = TemplateStringParam.Replace("$ADDR5$", Addr5.ToUpper)

            Return TemplateStringParam

        End Function