Ok, take note because this one may be very useful to everyone changing from another host to DH.
As you know, you can create a fully hosted domain on DH before changing the DNS servers on your registrar. This is good on one hand, but makes the process of moving files and databases a little bit more difficult, as the domain exists on the internal DH network but points to a different IP from the rest of the internet.
So, how can you upload your database if you can´t access, say, mysql.yourdomain.com yet? And how can you see what you´ve already uploaded if your domain points toa different IP? Well, what all the DH setup and welcome emails DON´T tell you is that you can ALWAYS create subdomains on dreamhosters.com free of charge to solve these problems. Take note:
First go to Domains::Add Domain on the panel and create a MIRROR to your fully hosted domain on a subdomain under dreamhosters.com. Let´s call it foobar.dreamhosters.com for illustration purposes.
After some time, foobar.dreamhosters.com will point to the web service on your fully hosted domain. Problem one solved: you can already see your site at http://foobar.dreamhosters.com before transferring the DNS permanently. This subdomain will show up just like a ¨real¨ domain on your panel and lets you create email addresses and other sub-subdomains (like mysql hosts) under it.
After that you simply go to Goodies::MySQL on the panel. If you already created a database and a mysql host under your domain, click on ¨Add host¨ and add a host mysql.foobar.dreamhosters.com to you database. If you haven´t done this yet, create your database and the host at once. After the usual setup time, it´s possible to access phpMyAdmin through http://mysql.foobar.dreamhosters.net and do whatever you need to do with it.
When everything is in place and working, all you have to do is change the DNS record on your registrar and everything will keep working fine. You can delete you *.dreamhosters.com subdomains after that if you like (don´t forget to change the mysql configuration on your scripts!) or keep them for emergencies - nobody will take them from you and they are free after all.
This sort of thing should be included on the welcome emails - I´m surely not the only one to move a site from one host to DH trying to make it seamlessly. Anyway, now this is at least on this forum. Hope it helps.
Oh, and kudos to Andrea from the support staff to come up with this solution!
As for the bugs on the DH panel: these weren´t solved yet. Nobody´s perfect anyway.
Happy new year everyone!