Use Web services in Nav 2009 SP1

Hi All,

I want to do following process outside NAV:

[Outside Navision Process]: I want to create new Purchase request and want to call Navision validations and insert data in Nav DB, and want to call Navision approval process and show the status of their request approval.

[Inside Navision Process]I want to create PO in Navision for the above PR's.

My client is using the classic client of 2009 SP1 version. Is it possible to use web-services in classic client for this or if there is any convenient way to do this.(New for this kind of work).

One important thing, the server for my client is shared with one more client which is at Navision 2009 R2 RTC client. 

Please suggest.

Thanks in advance.

Regards

Bheem