Custom FBA - authenticated user has no permission

We implemented a custom membership and role provider with custom SQL we successfully validating user and authenticating them into sharepoint using custom login but we have an issue that user has viewonly permission only and cannot do any action such as adding list or approving tasks even though we added FBA user to site owner group manually but with no affect, any help what could be missing.

steps we followed to implement custom FBA

- created custom membership provider implementing

• FindUsersByEmail
• FindUsersByName
• GetUser(string, bool)
• GetUser(object, bool)
• GetUserNameByEmail
• ValidateUser

- created custom role provider implementing

• GetRolesForUser
• RoleExists

deployed in gac and registered web.config as required and configured people picke and finally go to login page enter username and password then successfully authenticated and login to sharepoint with viewonly.

custom login sign-in code

 private void SignInProcess()
        {
            Boolean IsValidUser = false;
            String UserName = txtEmpNumber.Text;
            String Password = txtPassword.Text;

            IsValidUser = Membership.ValidateUser(UserName, Password);

            if (IsValidUser)
            {
                SecurityToken Token = GetSecurityToken(UserName, Password);
                if (Token != null)
                {
                    SPFederationAuthenticationModule.Current.SetPrincipalAndWriteSessionToken(Token);
                }
            }
        }

Please advise what I'm missing to be able to give user other permission level such as contribute or administartor