Character field length restriction

Hi, I have an issue. I have a field in my smartform. I have declared it as char1024. But still it considers only 256 characters,rest values are no entering into the field. I tried it with string , lchar but no use. Even if I declare the field with increased length it always considers only 256 characters. I have the same issue in programs also. Is this restriction of 256 lengh done by the basis.Because SAP provides an option for more than 1024 characters but in my case only 256 lenght characters are only being considered.

Thanks & Regards,

Siva.