some apointment values not carring forward to page

[Doug]

in myDbSchedulerProvider (through webservice) > GetAppointments

I can set apt.Start , apt.Description , apt.ID , apt.Subject and those carry forward to the page.

apt.Subject = dr("Title")
apt.Start = DateTime.SpecifyKind(StartTime, DateTimeKind.Utc)
apt.Description = dr("Content")

apt.CssClass = "mapping" & dr("Category").replace(";", "")
apt.ForeColor = Drawing.Color.Beige
apt.BackColor = Drawing.Color.Coral
apt.Attributes("class") = "mapping" & dr("Category").replace(";", "")

but if I set any of these values, they do not carry forward.
apt.CssClass , apt.ForeColor , apt.BackColor , apt.Attributes("class")

in the click appointment javascript event I alert these values and they are blank or null
but as I said, if I alert the other ones they give correct values.

function OnClientAppointmentClick(sender, args) {
alert(apt.get_start().format("MM/dd/yyyy HH:mm")) ; //<-- good value
alert(apt.get_description()); //<-- good value

alert(apt.get_cssClass()); //<-- blank value
alert(apt.get_backColor()); //<-- null value

etc etc