Took me a minute to figure out how to reply to a PM. And italic text reverts to non-italicized when posting.
What post editor are you using?
Click your name up top here to go to your profile page.
Once you are there, click the tools (wrench) icon at the top.
On the resulting page, click Forum (Just below settings)
When you're on the forum page, look for editor type. What do you have selected there? If you don't have WYSIWYG selected, can you select that for a minute and save the changes, see if that is a more comfortable editor for you?