Application package 'androidmanifest.xml' must have a minimum of two segments

Application package 'androidmanifest.xml' must have a minimum of two segments

I am attempting to upload an already existing app to the Samsung store via
the 100% Indie website. But the automated submission process demands that
the apk file is simply nameofapp.apk with no "." characters allowed before
the ".apk". So I changed the package name in my manifest like so:
WAS: package="com.mycompany.mygame"
NOW: package="mygame"
But then I got the error - Application package 'androidmanifest.xml' must
have a minimum of two segments. And there appears to be no way round this.
I could just create my multi-segment signed apk and then manually rename
it... but I'm nervous as to whether this is kosher. Do I have any other
options?