Hello.
in the Player's manual there is an hint bout the fact that, if a character reaches the 11th level with all the needed multiclass feats, that character can swap an at will power with one of the multiclass.

is this correct or I have misunderstood?

I would like for a multiclassed character to use one at will from both its class (basci and multiclass)...

Tahnk you

Andrea

It's not a hint, it's a clear rule on page 209: "At 11th level, you can choose to replace one of your at-will powers with an at-will power from your second class." This is part of Paragon Multiclassing, and it can be taken as an alternative to any of the other Paragon Paths (and yes, you do need to take four multiclass feats as a prerequisite). Given all the good stuff other Paragon Paths have, like permanent bonuses and special bonuses activated by the use of an action point, it's a big deal, but it's certainly a viable option.

Two other things you might be interested in: Versatile Master is a feat for Half-Elves that makes Paragon Multiclassing better for that race (found in Player's Handbook 2 or the Character Builder). Hybrid Class is a new class choice that gives your character the elements of two different classes starting at Level One, including one at-will from each class. This can be found in the upcoming Player's Handbook 3 or the Character Builder.

Have Fun!