Your application must have 10 application icons set on [Your-App-Name]-app.xml file that stores app manifest values.

Here are the sizes:

16X16
29x29
32X32
36X36
48X48
57X57
72X72
114X114
128X128
512X512

so when you set them in your manifest file,do as I did:

<icon>
     <image16x16>Images/icon16.fw.png</image16x16>
     <image29x29>Images/icon29.fw.png</image29x29>
     <image32x32>Images/icon32.fw.png</image32x32>
     <image36x36>Images/icon36.fw.png</image36x36>
     <image48x48>Images/icon48.fw.png</image48x48> 
     <image57x57>Images/icon57.fw.png</image57x57> 
     <image72x72>Images/icon72.fw.png</image72x72>   
     <image114x114>Images/icon114.fw.png</image114x114> 
     <image128x128>Images/icon128.fw.png</image128x128>   
     <image512x512>Images/icon512.fw.png</image512x512> 
</icon>

After you exported the build, you'll have your [AppName].ipa file to publish at iTunes Store.