How to add Billing permission to .apk file?

I’m using SOOMLA Plugin for in-App purchase in my game. After uploading the .apk file i’m trying to create purchase item ID but it shows following message.

“Your app doesn’t have any in-app products yet.
To add in-app products, you need to add the BILLING permission to your APK”

Though my AndoidManifest.xml file contains the permission for billing
uses-permission android:name="com.android.vending.BILLING

Any Help would be appreciated
Thanks in Advance

This is what happened to me:

  1. Downloaded Soomla plugin
  2. Went to Google Play to add a product, saw permission was required
  3. Looked at manifest file, saw that permission was already there

But the issue is that I had uploaded my last APK before I had downloaded Soomla, and Soomla is what had added the permission.

So what I should have done was

  1. Download Soomla Plugin
  2. Build and Upload APK
  3. Go to Google Play to add Product, permission will have been detected
  4. Profit

I rebuilt my APK and uploaded it as a Beta APK to Google Play and that resolved my issue.