[contact form 7] using custom fields [select]

Hello,

I have modified the text.php module of contact form 7 according to this post: https://www.ads-software.com/support/topic/313287?replies=4

a great solution by the way.

With this code, you can get the value of any custom field of your post and display it in the contact form text field.

What i am searching is:

A similar solution to use a post’s custom field, only with the [select] option.
So i probably have to edit the select.php module, but I don’t know that much php so im stuck.

Is there anyone who can help me out?