ipad - UINavigationController with custom vertical button bar -

i need implement navigation based app custom made button bar stays on vertical size of screen, similar reeder ipad app (see reeder screenshot). best way achieve result? thought adding bar subview of uinavigationcontroller , calling methods (like pushviewcontroller:animated:) via parentviewcontroller reference button bar view controller, seems bit convoluted.

might work, dangerous: set transform on calayer object of uinavigationbar. transform rotates bar "-1 * m_pi_2" right, might need translate few pixels too, position correct.

definitely works, more effort: render custom navbar, implement delegate protocol uinavigationcontroller, , listen nav changing, , implement own animations inside callbacks.

(i've done latter method provide custom uinavigationbars - works fine)

the caveat latter method animations might pause / delay because default wait each other finish. if @ uiview animations, there's setting says "play immediately, if other animations in progress", , might need set yes.