How can I upload package for several ubuntu versions to Launchpad automatically?

See the title.

I using dput and in my /etc/dput.cf :

[ppa]
fqdn        = ppa.launchpad.net
method      = ftp
incoming        = ~onto/onto/ubuntu/
login           = anonymous
allow_unsigned_uploads  = 0

But it build only for version in debian/changes, but i want build for another versions too.

How to do it?

I think you should look at this question that I asked, and got answered:

PPA & Packaging: Having versions of packages for multiple distros

You'd have to package multiple times to get each version of Ubuntu, however you can upload a package for one version, then copy it over to each other version. For instance, I build packages for Lucid, however the same package is compatible with Maverick and later. As such, using the instructions in the aforementioned link, I copy it over to Maverick and Natty within the PPA, and the system then copies/builds it in the background and then publishes the data to the PPA when its done copying.