c# - WCF - Generating and consuming WSDL using SoapUI + Error -

hello developers i'm new in wcf in generating wsdl , consuming using soapui. have questions:

the first thing, have developed string datamember designed mandatory datatype using isrequired=true, in generated wsdl these datatypes exposed mandatory dissapearing of minocurr = 0, there still field nillable=true (the reason string datatypes implements string.empty default behaviour), has no corresponding mandatory, nill=true means can pass null value throught these fields. u know how fix it?

the second thing similar first, in case datacontract, when load wsdl in soapui observe put in data format tag optional above datacontract, means can erased, in case these datacontract mandatory, when observe in wsdl on these datacontract exist fu.... tag nullable=true, raise out similar question is: u know how fix it?

and finally, have field char datatype, in soapui when consume webservice sending data can pass letter char solution sending ascii character, eg: if wanna pass letter 'j', need put 74, want know way implement can pass real letter throught soapui.