samba - Aug 2012 - Schema modification with auxiliary class vs builtin class and vbscript

Hello

The situation is the following :

I've successfully created an auxiliary class with an attribute by 
following this method :

     
http://semifershome.free.fr/semifer/index.php?2008/02/12/42-etendre-le-schema-active-directory-classes-attributs-et-display-specifiers

The auxiliary class  is "allowedService" and the attribute is 
"allowedServiceAttribute".

The following VB script for changing the attribute doesn't run for the 
bold line. The first time we run the script we have the following error 
but the value of allowedServiceAttribute is successfully setted:

/Erreur : Cet objet ne g?re pas cette propri?t? ou cette m?thode 
"allowedServiceAttribute"/

But even if we run another time the script we have the following same 
message (so we can see the previous value).

The VB Script (example script)
----------------------------------------------------------------------------------------------------------------------------------------------
dim args
dim user
dim temp

set args = wscript.arguments
set user = GetObject(args(0))

on error resume next
*temp = InputBox("Service attribute : " , ,
user.allowedServiceAttribute)*
user.put allowedServiceAttribute", "test value"
user.setinfo


set user = Nothing
set args = Nothing

wscript.Quit
----------------------------------------------------------------------------------------------------------------------------------------------

Where I do not understand is that for another auxiliary class 
(PossixAccount) and another attribute (LoginShell) the bold line is ok :

*temp = InputBox(Loginshell : " , , user.LoginShell)*

and we can see the previous value of LoginShell if we have already 
setted it.

Here are the ldiff files of the auxiliary class and his attribute :

dn: CN=allowedService, CN=Schema,CN=Configuration,DC=sc,DC=isc84,DC=org
mayContain: allowedServiceAttribute
objectClass: top
objectClass: classSchema
defaultObjectCategory: 
CN=allowedService,CN=Schema,CN=Configuration,DC=sc,DC= isc84,DC=org
defaultSecurityDescriptor: 
D:(A;;RPWPCRCCDCLCLORCWOWDSDDTSW;;;DA)(A;;RPWPCRCC 
DCLCLORCWOWDSDDTSW;;;SY)(A;;RPLCLORC;;;AU)
objectCategory: 
CN=Class-Schema,CN=Schema,CN=Configuration,DC=sc,DC=isc84,DC=org
schemaIDGUID:: ee+/vURt77+9H++/vUHvv73vv73nsJLvv70d77+9
subClassOf: top
cn: allowedService
objectClassCategory: 3
lDAPDisplayName: allowedService
showInAdvancedViewOnly: TRUE
distinguishedName: 
CN=allowedService,CN=Schema,CN=Configuration,DC=sc,DC=isc84,DC=org
whenChanged: 20120824065037.0Z
whenCreated: 20120823124813.0Z
governsID: 
1.2.840.113556.1.8000.2554.6382.11911.19017.19847.32977.12302487.3262913.1
adminDisplayName: allowedService
objectGUID:: UB9G77+9GwoVTO+/vUjvv71s77+977+9
rDNAttID: uid
uSNChanged: 7129
uSNCreated: 7110
instanceType: 4
adminDescription: allowedService
name: allowedService

dn: CN=allowedServiceAttribute, 
CN=Schema,CN=Configuration,DC=sc,DC=isc84,DC=org
objectClass: top
objectClass: attributeSchema
oMSyntax: 64
objectCategory: 
CN=Attribute-Schema,CN=Schema,CN=Configuration,DC=sc,DC=isc84,DC=org
isMemberOfPartialAttributeSet: TRUE
schemaIDGUID:: 77+9GUrvv70WCu+/vUzvv71T77+976SjCu+/vQ=cn:
allowedServiceAttribute
isSingleValued: TRUE
lDAPDisplayName: allowedServiceAttribute
showInAdvancedViewOnly: TRUE
searchFlags: 23
attributeID: 
1.2.840.113556.1.8000.2554.6382.11911.19017.19847.32977.12302487.3262913.1.1
distinguishedName: 
CN=allowedServiceAttribute,CN=Schema,CN=Configuration,DC=sc,DC=isc84,DC=org
whenChanged: 20120824065737.0Z
whenCreated: 20120823124919.0Z
msDS-IntId: -1322168606
adminDisplayName: allowedServiceAttribute
objectGUID:: 77+9eTDvv73vv73vv70EQe+/vSwKXgRA77+9
attributeSyntax: 2.5.5.12
uSNChanged: 7133
uSNCreated: 7113
instanceType: 4
adminDescription: allowedServiceAttribute
name: allowedServiceAttribute

Any idea ?