Localized nib file dont take localized image into account-Collection of common programming errors

I have 2 localized directories ca.lproj and es.lproj. Both own a nib MyNib.xib and an icon MyIcon.png. MyIcon.png is used in a custom button in the nib. Because MyIcon.png has a text in it, the actual image is different for each folder, with the text drawn in the correct language. I need each nib to embbed the correct icon.

The problem is that if I open the nib in one lproj ( say the es.lproj ) and try to assign the icon to the button in IB, I can only see the icon that belong to the OTHER lproj ( the ca.lproj ). As a result, I can only have the wrong icon in the nib.

I have checked that each icon and each nib is properly localized, but I can not find out why the es.lproj nib doesnt display only the es.lproj icons.

Thanks in advance.