ObjectQuery SkuInfo Join error

I'm using the ObjectQuery API to retrieve data from a custom table which is generated by Kentico and inherits from SKUTreeNode. When I join it with the Com_Sku table ( with SKUInfo ), I'm getting an error.

The example code I use is: var test = CustomProductProvider.GetCustomProducts() .Source(sourceItem => sourceItem.Join<SKUInfo>("no", "SKUNUMBER")).FirstOrDefault();

The error is "Invalid column name 'no'.", while this column belongs to the product table.

The query which is generated is ( I excluded the where-clause ):

SELECT * FROM View_CMS_Tree_Joined AS V WITH (NOLOCK, NOEXPAND) INNER JOIN custom_product AS C WITH (NOLOCK) ON V.DocumentForeignKeyValue = C.tableID AND V.ClassName = N'custom.product' LEFT OUTER JOIN COM_SKU AS S WITH (NOLOCK) ON V.NodeSKUID = S.SKUID INNER JOIN COM_SKU ON S.no = COM_SKU.SKUNUMBER

Why can't I join or how can I retrieve the information in the custom table joined by the COM_SKU table?