Can't delegate calendar permissions with Office 365 Trial?

Hi,

I'm trying Office 365 for small business before buying it. I'm using emails created on xxx@xxxcompanyxxx.onmicrosoft.com

Everything is OK except calendar delegation.

I can't delegate "full" calendar permission, only "reviewer".

I saw in some blog posts that PowerShell commands can allow right management, but how could I do so for the trial session?

Is this a limitation for the trial?

Thanks

Vanessa.