preseed: preserve home folder

[zindine]

I am looking for a way to preserve the home folder (if present) at installation time using a preseed file?

I understand the home folder has to be on a different partition and I found about this https://wiki.ubuntu.com/UbiquityPreserveHome but I can't figure the command to put in the preseed file.

Thanks

[zindine]

Any ideas? Is there a better place to ask this question?

Thanks