Graphics scale-down issue on iPhone3 (happens also on Corona simulator for iPhone3)

My config.lua file is:

application={  
 content = {  
 width = 480,  
 height = 800,  
 scale = "zoomStretch",  
 }  
}  

Display graphics scale-UP looks ok for all devices that we tested, but we have a problem with scale-DOWN to iPhone3. Please see the screenshot that shows the difference for iPhone4 Corona simulator and for iPhone3 Corona simulator.
http://www.11sheep.com/temp/iphone3_screen_bug.jpg

Why does it happens? And what is WA that we can do for it fixing? Thanks
[import]uid: 172733 topic_id: 33229 reply_id: 333229[/import]