title: Change AppId using [Code] just before the installation in Inno Setup
body: <p>In a setup I give the user the option to install either a 32 or 64 bit version using radio buttons.</p>
  <p>I then want to append either <code>_32</code> or <code>_64</code> to the <code>AppId</code>.</p>
  <p>I know I can change the <code>AppId</code> using scripted constants but the needed function is called while Setup is starting. But at this point the radio buttons do not yet exist and thus I receive the error &quot;Could not call proc&quot;.</p>
  <p>I consulted the Inno Setup help and I read that you can change the <code>AppId</code> at any given point before the installation process has started (if I understood correctly).</p>
  <p>So how do I manage to do this?</p>
  <p>I am looking forward to your answers!</p>