This is the code to create a lookup property for my custom entity
Lookup salesPersonLookup = new Lookup(“new_salesperson”, crmkey.Value);
LookupProperty lookupProperty = new LookupProperty(“new_salespersonid”, salesPersonLookup);
first you need to create a lookup, this has the syntax of
new Lookup(“entity name”, guid of entity to lookup)
then you need to add the lookup into a LookupProperty
new LookupProperty(“field name”, Lookup)
You then add this property to your property bag and you will be able to update that property
