I want to create a custom icon for my database template as opposed to the standard fmp icon. I am able to do this for my file on Mac, however the icon does not always remain when emailed or transferring to Windows. Is there a way to map an icon for my solution that will remain there permanently?

I'm almost certain a Mac icon won't transfer across to a Windows machine: the OS displays the icons and they use completely different mechanisms.

You might try changing the icon on a windows machine and sending that.

I've never been detailed enough to mess with the icon of the parent file, but chagin ghte icon for a shortcut is easy and doens't require any special tools. Simply righ clicking and going to properties of the icon lets you choose a new one.