Hi Husin,
I had several conversion issues with SAP_GWFND SP13. Please try following notes.
2181284 - Runtime error in /IWCOR/CL_DS_EP_WRITER_XML - property of type Edm.DateTime or Edm.DateTimeOffset
2245413 - Truncated filter values
2241188 - Some characters of filter value get cut in OData request
2232883 - Wrong values in select options table
2249354 - Double properties in select table
Regards,
Masa / SAP Technology RIG