Faults in a webservice

[rjones1981]

I have a general question about how to propery architect a webservice in respect to error handling. We we encounter an error in the webservice that we want to return to the client is it best to return that as a type that we create or package it into a soap fault and return that? I am including an example of what we have now. I want to know if we should go the soap fault route and why. For some reason I am stuck on this point. Please chime in and correct the error of my ways!!!

<xs:element name="ValidateCPNIRequest">
   <xs:complexType minOccurs="0" maxOccurs="1">			
      <xs:sequence>
         <xs:element name="accountNumber" type="ei:AcctNumType"/>
         <xs:element name="userCPNI" type="ei:UserCPNIType"/>
         <xs:element name="mmaUserID" type="ei:MMAUserIdType"/>
         <xs:element name="idType" type="ei:IdType" minOccurs="0" maxOccurs="1" />
         <xs:element name="idNumber" type="ei:IdNumberType" minOccurs="0" maxOccurs="1" />
         <xs:element name="authUserID" type="ei:CPNIUserIdType" minOccurs="0" maxOccurs="1" />
      </xs:sequence>
    </xs:complexType>

    <xs:complexType minOccurs="0" maxOccurs="1">
          <xs:element name="faultResponse" type="xs:string"/>
    </xs:complexType>
</xs:element>