Hello,
Thank you for your message.
To have a custom label for the submit button on my profile you would have to create a custom webpart. Only the default "OK" text is available on the button when added through the alternative forms section.
The following discussion discusses this idea of customizing a web part and might be able solve your question:
link text
Please let me know if you have any further questions.
Best Regards,
Nicholas Beichley
Junior Support Engineer