Update of Entity Metadata in CRM Online (Price List Item)

Hi,

We have an on-premise solution with a custom attribute added to the Price List Item entity. 

Now we want to recreate this attribute in CRM Online and given that the Price List Item is not a customizable entity we wanted to set the properties "IsCustomizable" and "CanCreateAttributes" to true.

I've created a plugin that is executed on the creation of a Price List Item with the following code:

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RetrieveEntityRequest retrieveProductPriceLevelEntityRequest = new RetrieveEntityRequest
{
LogicalName = "productpricelevel"
};

RetrieveEntityResponse retrievePriceListItemEntityResponse = (RetrieveEntityResponse)service.Execute(retrieveProductPriceLevelEntityRequest);
EntityMetadata priceListItemEntity = retrievePriceListItemEntityResponse.EntityMetadata;

//throw new InvalidPluginExecutionException("is customizable -> " + priceListItemEntity.IsCustomizable.Value);

priceListItemEntity.IsCustomizable = new BooleanManagedProperty(true);
priceListItemEntity.CanCreateAttributes = new BooleanManagedProperty(true);

UpdateEntityRequest updatePriceListItemRequest = new UpdateEntityRequest
{
Entity = priceListItemEntity
};

service.Execute(updatePriceListItemRequest);

PublishAllXmlRequest publishRequest = new PublishAllXmlRequest();
service.Execute(publishRequest);
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While the plugin is executed successfully and when I debug it, I can see that the "IsCustomizable" and "CanCreateAttributes" fields are set to "true", I still can't add new fields to the Price List Item.

So I want to ask - are there any additional attributes that I need to set, and if not - what could be the problem?

Thanks.

Best regards,

Evgeni