Stack Trace If anyone is interested:

System.Web.Services.Protocols.SoapException: Server was unable to process
request. ---> System.InvalidOperationException: Method
TestImpl.PrintPaperwork can not be reflected. --->
System.InvalidOperationException: There was an error reflecting
'PrintPaperworkResult'. ---> System.InvalidOperationException: There was an
error reflecting type 'DCMWS.PrintPaperworkResponse'. --->
System.InvalidOperationException: There was an error reflecting property
'PDF'. ---> System.InvalidOperationException: There was an error reflecting
type 'System.Byte'. ---> System.InvalidOperationException: 'base64Binary' is
an invalid value for the XmlElementAttribute.DataType property. base64Binary
cannot be converted to System.Byte. at
System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping(TypeModel
model, String ns, ImportContext context, String dataType, Boolean repeats)
--- End of inner exception stack trace --- at
System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping(TypeModel
model, String ns, ImportContext context, String dataType, Boolean repeats) at
System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping(TypeModel
model, String ns, ImportContext context, String dataType) at
System.Xml.Serialization.XmlReflectionImporter.ImportAccessorMapping(MemberMapping
accessor, FieldModel model, XmlAttributes a, String ns, Type
choiceIdentifierType) at
System.Xml.Serialization.XmlReflectionImporter.ImportFieldMapping(StructModel
parent, FieldModel model, XmlAttributes a, String ns) at
System.Xml.Serialization.XmlReflectionImporter.ImportStructLikeMapping(StructModel
model, String ns) --- End of inner exception stack trace --- at
System.Xml.Serialization.XmlReflectionImporter.ImportStructLikeMapping(StructModel
model, String ns) at
System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping(TypeModel
model, String ns, ImportContext context, String dataType, Boolean repeats)
--- End of inner exception stack trace --- at
System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping(TypeModel
model, String ns, ImportContext context, String dataType, Boolean repeats) at
System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping(TypeModel
model, String ns, ImportContext context, String dataType) at
System.Xml.Serialization.XmlReflectionImporter.ImportAccessorMapping(MemberMapping
accessor, FieldModel model, XmlAttributes a, String ns, Type
choiceIdentifierType) at
System.Xml.Serialization.XmlReflectionImporter.ImportMemberMapping(XmlReflectionMember
xmlReflectionMember, String ns, XmlReflectionMember[] xmlReflectionMembers)
at
System.Xml.Serialization.XmlReflectionImporter.ImportMembersMapping(XmlReflectionMember[]
xmlReflectionMembers, String ns, Boolean hasWrapperElement) --- End of inner
exception stack trace --- at
System.Xml.Serialization.XmlReflectionImporter.ImportMembersMapping(XmlReflectionMember[]
xmlReflectionMembers, String ns, Boolean hasWrapperElement) at
System.Xml.Serialization.XmlReflectionImporter.ImportMembersMapping(String
elementName, String ns, XmlReflectionMember[] members, Boolean
hasWrapperElement) at
System.Web.Services.Protocols.SoapReflector.ImportMembersMapping(XmlReflectionImporter
xmlImporter, SoapReflectionImporter soapImporter, Boolean
serviceDefaultIsEncoded, Boolean rpc, SoapBindingUse use, SoapParameterStyle
paramStyle, String elementName, String elementNamespace, Boolean nsIsDefault,
XmlReflectionMember[] members, Boolean validate) at
System.Web.Services.Protocols.SoapReflector.ReflectMethod(LogicalMethodInfo
methodInfo, Boolean client, XmlReflectionImporter xmlImporter,
SoapReflectionImporter soapImporter, String defaultNs) --- End of inner
exception stack trace --- at
System.Web.Services.Protocols.SoapReflector.ReflectMethod(LogicalMethodInfo
methodInfo, Boolean client, XmlReflectionImporter xmlImporter,
SoapReflectionImporter soapImporter, String defaultNs) at
System.Web.Services.Protocols.SoapServerType..ctor(Type type, ProtocolsEnum
versionsSupported) at
System.Web.Services.Protocols.SoapServerProtocol.Initialize() at
System.Web.Services.Protocols.ServerProtocol.SetContext(Type type,
HttpContext context, HttpRequest request, HttpResponse response) at
System.Web.Services.Protocols.ServerProtocolFactory.Create(Type type,
HttpContext context, HttpRequest request, HttpResponse response, Boolean&
abortProcessing) --- End of inner exception stack trace ---