Add custom pages AND external .isi file in setup script?

Question

Is there a way for an Inno Setup script to include code that creates custom pages AND an external .isi file (I'm using the ISSI add-in.) If I try to use both, I get the error message that says "Duplicate Identifier: INITIALIZEWIZARD" because (obviously) the identifier occurs both in my main script and in the add-in.

Here (incomplete!) is the code I want to use to create a custom page (I've taken it almost entirely from the examples supplied with Inno Setup:

procedure CreateTheWizardPages;

var
 Page: TWizardPage;
 RichEditViewer: TRichEditViewer;
 vDosFolder: String; 
begin
 if RegQueryStringValue(HKEY_CURRENT_USER, 'Software\WPDOS.org','vDosDir', vDosFolder) then 
 begin

if ((DirExists(vDosFolder + '\62Config')) OR (DirExists(vDosFolder + '\61Config')) OR (DirExists(vDosFolder + '\51Config'))) then
  begin

Page := CreateCustomPage(wpInfoBefore, 'Existing installation found', 'Read this message!'); 

RichEditViewer := TRichEditViewer.Create(Page);
RichEditViewer.Width := Page.SurfaceWidth;
RichEditViewer.Height := Page.SurfaceHeight;
RichEditViewer.Parent := Page.Surface;
RichEditViewer.ScrollBars := ssVertical;
RichEditViewer.UseRichEdit := True;
RichEditViewer.RTFText := '{\rtf1\ansi\ansicpg1252\deff0\deflang1043{\fonttbl{\f0\fswiss\fcharset0 Arial;}}{\colortbl ;\red255\green0\blue0;\red0\green128\blue0;\red0\green0\blue128;}\viewkind4\uc1\pard\f0\fs20 R\cf1 ead\cf2 This\cf3 Message!\cf0\par}';
RichEditViewer.ReadOnly := True;

end;

  end; 
end;

procedure InitializeWizard();
begin
  CreateTheWizardPages;
end;

What I also want to do (if possible) is us the ISSI addin to put a clickable link on status bar of the wizard, but if I include this code I get the error message:

[ISSI]
#define ISSI_English
#define ISSI_URL
#define ISSI_URLText
#define ISSI_IncludePath "X:\ISSI"
#include ISSI_IncludePath+"\_issi.isi"

Plus, of course, some lines in Custom Messages spelling out what ISSI is supposed to display.

If there's any way to have both these things, I'll be grateful to hear it.

Answer 1

To make life easier for anyone else who wants to do this, the answer is here, though a bit obscure:

http://members.home.nl/albartus/inno/ISSI_Functions/ISSI_MyNextButtonClick.htm

To sum this up, if you have an existing section that looks like this:

[ISSI]
#define ISSI_English
#define ISSI_URL
#define ISSI_URLText
#define ISSI_IncludePath "X:\ISSI"
#include ISSI_IncludePath+"\_issi.isi"

Do the following:

(1) add this line in [ISSI] block shown above.

#define ISSI_UseMyInitializeWizard

(2). Go the end of your Pascal code, and add three lines, including the line that ends the [CODE] block as shown here:

[/CODE]
#define ISSI_IncludePath "X:\ISSI"
#include ISSI_IncludePath+"\_issi.isi"

and REMOVE those last two lines from the [ISSI] block, because you're adding them here.

(3) Then, inside your code block, find the lines that read:

procedure InitializeWizard(); 
...
end;

and change the first of these lines to read:

procedure ISSI_InitializeWizard();     // ISSI_ added to string

Problem solved. I hope this is a clearer statement than the ones I found out there in the wild.