problem - configuring MySQL for postfix/courier catch-all

I've got Postfix working with Courier and MySQL, but now want to set up catch-all mail accounts. But how? I am particularly confused about using MySQL for virtualaliasmaps. I guess I have to somehow cross-reference existing tables, and maybe create a catchall table for each domain. (I have next to no experience playing with this.)

My main.cf reads …

smtpdbanner = $myhostname ESMTP $mailname (Ubuntu)

biff = no

appenddotmydomain = no

readme_directory = no

smtpdsaslauth_enable = yes

brokensaslauth_clients = yes

smtpdsaslauthenticated_header = yes

smtpdrecipientrestrictions = permitmynetworks, permitsaslauthenticated, rejectunauth_destination

smtpdusetls = yes

smtpdtlscert_file = /etc/ssl/certs/mailcert.pem

smtpdtlskeyfile = $smtpdtlscertfile

myhostname = mail.mydomain.com

alias_maps = hash:/etc/aliases

alias_database = hash:/etc/aliases

myorigin = /etc/mailname

mydestination =

relayhost =

mynetworks = mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128

mailboxsizelimit = 0

recipient_delimiter = +

inet_interfaces = all

virtualaliasdomains =

virtualaliasmaps = proxy:mysql:/etc/postfix/mysql-forwards.cf, mysql:/etc/postfix/mysql-email.cf

virtualmailboxdomains = proxy:mysql:/etc/postfix/mysql-domains.cf

virtualmailboxmaps = proxy:mysql:/etc/postfix/mysql-mailboxes.cf

virtualmailboxbase = /home/vmail

virtualuidmaps = static:5000

virtualgidmaps = static:5000

…

Would I be right in thinking I need to change the above to:

myhostname = localhost

virtualaliasdomains = mydomain.com mydomain2.com another.tld

And .. well, here's where I am most confused what to do…

virtualaliasmaps = proxy:mysql:/etc/postfix/mysql-forwards.cf, mysql:/etc/postfix/mysql-email.cf # What do I do here??

…

Were I not using MySQL, I guess I would set up /etc/postfix/virtual map file and add something like:

@mydomain.com newbie@mydomain.com

@another.tld newbie@mydomain.com

… but as I have created mySQL tables for domains, users, email and forward, I am guessing I need to do something different,

…and thought I would ask before messing everything up.

Any pointers greatly appreciated.