Android Certificate/signing application

I tried to update my app on the android market and I got this error : The apk must be signed with the same certificates as the previous version.

Since I just had a couple of downloads, I unpublished it and released it with a new package. I made new certificates, keystore, and alias with eclipse and made back ups of the certificate files. I released it and tried to update the new app some days after. I got the same error on the new app.

1. 
   

   
   I use advanced mode(multiple apks) in the android market, with 2 apks. This is how I signed the app and update it.
   

   
   


2. 
   

   
   Android Tools/Export signed android application. Created a new keystore and a alias and exported it as a apk. The other file, exported I by creating a new keystore and a alias.
   

   
   

When I updated this. I did 1, and instead of creating a new keystore i: Use exsisting keystor and alias. I used the same password. Apk nr2: Use the exisiting keystore to the apk 2 and same alias and same password, but still I get these errors.

This is going to be the 3rd time I need to upload a new application because of these errors. Any Solutions?