Here are the commands I used:

stsadm -o addcontentdb -url http://moss:1000 -databasename SharePoint_AdminContent_moss
stsadm -o enumsites -url http://moss:1000 > output.txt
stsadm -o mergecontentdbs -url http://moss:1000 -operation 2 -sourcedatabasename SharePoint_AdminContent_f58aa288-57e9-49ff-b953-9b4d53d50bfc -destinationdatabasename SharePoint_AdminContent_moss -filename output.txt
iisreset
stsadm -o deletecontentdb -url http://moss -databasename SharePoint_AdminContent_f58aa288-57e9-49ff-b953-9b4d53d50bfc
check with stsadm -o enumcontentdbs -url http://moss:1000