HOw to add items to CDO Fields collection?

[eperales]

Hi All,

I'm trying to implement a Knowledge Base article
(http://support.microsoft.com/?kbid=174211) in C# to use
SENT_REPRESENTING Properties. But I'm unable to set the PropsetID of
the Fields.Add. I keep getting and E_INVALIDARG error.

field=(MAPI.Field)fields.Add(
String.Empty,
MAPI.CdoFieldType.CdoEmpty,ae.Type,
MAPI.CdoPropTags.CdoPR_SENT_REPRESENTING_ADDRTYPE) // <-- HERE

this does compile but does not seems to set the propset id:

field=(MAPI.Field)fields.Add(
"PR_SENT_REPRESENTING_EMAIL_ADDRESS",
MAPI.CdoFieldType.CdoEmpty,ae.Address,
Missing.Value);

Does anybody know what is the right combination of arguments to make
this work?

Thanks in advance

eperales