I implemented this exact example in my POS for the product availability custom control : docs.microsoft.com/.../pos-control-non-screen. I do not see anything specific for localization in this link. It works 100% on my Dev box.
I created a deployable package using LCS with the setup in: docs.microsoft.com/.../integrate-retail-sdk-continuous-build.
After uploading the deployable package into the asset library on LCS, when we click on the "Manage" link under Environment features on the sandbox environment set up for Retail and then Update Extension and choose the deployable package from the list, it ran through 9 steps successfully.
Then I log onto POS and click on Settings:
When I click on View Details I see that the custom control loaded successfully. But resources failed:
When I click on Resources it shows the following detail:
What does this mean?
When I look under $Dynamics 365/Trunk/RetailSdk-Main/Documents/Resources I see the 3 standard runtime resource files. So they would have made it into the deployable package I assume. I do not have any custom labels or messages at this point.