Insight Groovy Script - Email Template Not Found

[mooncake]

Hello,

I'm trying to write a post-function using insight groovy scripts.

Between other stuff, it should send an email, based on a template.

I've been following the "Send email from a product catalog order"
example: https://confluence.atlassian.com/insightapps/post-functions-1085180917.html

However I cannot figure out how to load the velocity html template, I tried multiple folders in the jira directory (scripts, data/templates/email, data/<custom_folder>) without success, every time it says "GroovyInsightException: Could not find template 'templates/email/handover.html' ensure it is in the classpath.' ".

Anyone knows where should my custom template be stored, and if anything has to be configured in a particular way?

The example does not give any additional hint apart "the templates are stored on the server", and the documentation is EXTREMELY lacking since atlassian took over mindville (Btw, to the atlassian team, please ensure all the old documentation is still available).