Including publishpress variables as custom fields when posting

Hi I am trying to post woocommerce products as events where the expiration date in publishpress future is the actual event date.

We are trying to automate event publishing and are pushing the following values as custom fields with hopes that publishpress will recognize them



{
"key": "_expiration-date",
"value": {{expiration_date_unix}}
},
{
"key": "_expiration-date-status",
"value": "saved"
},
{
"key": "_expiration-date-type",
"value": "category"
},
{
"key": "_expiration-date-taxonomy",
"value": "product_cat"
},
{
"key": "_expiration-date-categories",
"value": ["3206"]
},

but however we publish the custom meta fields Publishpress just defaults to the plugin settings (i.e) 1 week from publish date)

is there something we are missing?