Hi Gillg
I would suggest if you think the Joseph Voss who married Mary Ann Fuller is your ancestor that you order their marriage certificate online. As far as I know the cost is still $17.50 Aus. for an uncertified copy.
The link is
http://online.justice.vic.gov.au/bdm/homeThen scroll down the page to Historical Index and then click on Purchase & download an image. As you have all the details including the Registered Number, you should get notification almost immediately that the certificate is ready to download. It will be in PDF format, so I usually save it to Acrobat Reader and then print a copy from the web site. Having it saved in Acrobat means you can enlarge it to make reading the handwriting easier.
The information usually contained in the State of Victoria marriage certs is - When & where married; Name and Surname of the parties; Condition of parties: if widowed etc,children by each former marriage living & dead, and Birth place of parties; Rank & profession; Ages;Residence - present and usual; parents names and rank or profession.
So, as you see you should get the age,birthplace and parents names of the couple, plus you will also have the names of the witnesses to the marriage.
All invaluable when you want to look for them in the Uk census etc.
Noells