Alphanumeric Condition on a field

Hello Everyone,

In my Webdynpro Application, I need to include some validation on a Order Number field. The conditions that need to be set on the Order Number are

The first character should be an Alphabet and the rest should be numbers.......

Is it possible to put these conditions. I hope you can understand my requirements. Please let me know if it is not clear.

Regards,

Gopal.