SharePoint:功能基础

我有这个特点

<?xml version="1.0" encoding="utf-8"?>
<Feature  Id="c54f20d8-1ad1-49b8-aff7-2c874dd2f45a"
          Title="MyCompany Content Types"
          Description="Content Types required for MyCompany Provided Applications and Functionality"
         Version="12.0.0.0"
         Hidden="FALSE"
         Scope="Site"
         DefaultResourceFile="core"
         xmlns="http://schemas.microsoft.com/sharepoint/">
  <ElementManifests>
   <ElementManifest Location="siteColumns.xml"/>    
 </ElementManifests>
</Feature>

以下是siteColumns.xml的内容

<?xml version="1.0" encoding="utf-8" ?>
<Elements xmlns="http://schemas.microsoft.com/sharepoint/">
  <Field
     ID="{1F343F02-22D9-45b8-A2A8-CEB2619A28C4}"
     Name="AllowSubstDelivery"
     DisplayName="AllowSubstDelivery"
    Type="Boolean"
    Format="TRUE"
    Group="MyCustomGroup"
  />
 </Elements>

此功能将安装并激活,而不会产生错误,但是找不到site column,您知道为什么此sitecolumn不可见吗?

我检查了日志,也没有报告错误。