metas in pre orders plugin

hi, sorry to ask you, but for your plugin: preorders for woocommerce,
i need the metas names for variables products : no date message, product by date and preorder status:

for simple products, i fount it:

_simple_preorder (yes to activate preorders)

_wcj_product_by_date_direct_date ( the date of availability )

_wpro_no_date_label ( the custom prompt if the product is on preorder )

but for variable products, i don’t find them..

can you help me?

i have hundreds of variations, and i need meta to bulk edit products,
i can’t go in each products and set preorder “on”, the date, and the message for each ones…

we just install your plugin today and setting it at the moment.

best regards
al