how can i save a document from ipad onto idisk after i modify it?

[jawseds]

All the posts I see related to this are older and some say you can now do this, but I can't figure out how! Sorry if this is totally obvious and I'm not getting it

I saved documents onto iDisk from my computer. Then I worked on it on my ipad (in office2HD app), now I'd like to save modified document to idisk...any advice on how to do this without throwing ipad through window?