Please check if Belgium is selected for the address or if exists, the shipping address of the customer. Or leave the country field blank for this rate. You can also find some samples in chapter: 'Custom Shipping Rates'.
You must set country=BE for BelgiumYou can find the country codes in chapter: ‘The following countries are supported shipping destinations’.The Country and State/Province codes can also be found in the source code of the cart module address page -> right click on the site -> search for the Country or State/Province.<option selected="selected" value="UK">United Kingdom</option><option value="ANT">Antrim</option>State/Province codes are also listed under Host -> Lists -> expand the ‘Country’ node -> select the Country.The codes are case sensitive!