Remote Api Question Regarding Custom Fields.

Hello, I have been reading through all the docs I can possibly find. I'm not sure if I'm overlooking something or if what I'm attempting to do just isn't possible. During the create-domain Http call I am attempting to pass info into a custom field. I have tried many variations on how to do so.

Here is my call: https://awesomesite.com:10000/virtual-server/remote.cgi?program=create-d...

VIRTUALSERVER_FIELD_ZIP is the custom field id like to pass info to during domain creation.

These are my current available variables:

VIRTUALSERVER_EDIT_RESTORE=0 VIRTUALSERVER_NAME6=1 VIRTUALSERVER_VIRT6= VIRTUALSERVER_NETMASK= VIRTUALSERVER_LIMIT_WEBALIZER=1 VIRTUALSERVER_EMAILTO_ADDR=vartest@awesomesite.com.com VIRTUALSERVER_DB=vartest DOCUMENT_REALROOT=/usr/share/webmin VIRTUALSERVER_LOGROTATE=1 VIRTUALSERVER_MAILBOXLIMIT= BASE_REMOTE_USER=root VIRTUALSERVER_EDIT_SCRIPTS=0 VIRTUALSERVER_PREFIX=vartest VIRTUALSERVER_FIELD_FINANCING= VIRTUALSERVER_IP=xxxxxxxx VIRTUALSERVER_EDIT_SSL=0 HTTP_CONTENT_LENGTH=538 MYSQL_PWD=xxxxxxx VIRTUALSERVER_DB_MYSQL=vartest VIRTUALSERVER_LIMIT_WEB=1 VIRTUALSERVER_EDIT_SPF=0 VIRTUALSERVER_ALLOWEDSCRIPTS= VIRTUALSERVER_EDIT_DELETE=0 VIRTUALSERVER_SPAM=1 VIRTUALSERVER_EMAILTO_SRC=vartest@awesomesite.com VIRTUALSERVER_GID=1023 USERADMIN_GROUP=vartest VIRTUALSERVER_MAIL=1 VIRTUALSERVER_EDIT_ADMINS=0 VIRTUALSERVER_EDIT_DOMAIN=0 MINISERV_CONFIG=/etc/webmin/miniserv.conf VIRTUALSERVER_POSTGRES=0 VIRTUALSERVER_EDIT_DNSIP=0 HTTP_USER_AGENT=Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:53.0) Gecko/20100101 Firefox/53.0 VIRTUALSERVER_OWNER=var test VIRTUALSERVER_FIELD_LIC= SERVER_PORT=10000 VIRTUALSERVER_EDIT_SPAM=0 VIRTUALSERVER_LIMIT_WEBMIN=0 VIRTUALSERVER_FIELD_ZIP= GLOBAL_CITY= VIRTUALSERVER_EDIT_FORWARD=0

Using the cli I am able to use virtualmin modify-domain --set and set my field just fine from there but is it possible to add the info during server create? Thank you in advance.