It doesn't seem to be achievable through PI Web Services. The closest it gets to getting PI points properties and searching for them is the FindPIPathsBasic method which basically searches for PI tags satisfying certain criteria; and even then the creation date is not one of them.
By the way, you may want to use the appropriate forum for your questions to get the best exposure and fastest response from the community
Sandeep, I guess the easiest thing here would be to create a small webservice of your own, where you can use a simple OLEDB query to get the creation date you want.
SELECT creationdate FROM pipoint..classic WHERE tag='sinusoid'