Single Sign On using Webdynpro abap

Dear experts

We are starting with E-Recruiting project on our abap system 6.05 NW 7.02

Operating system is Redhat 6.x with Oracle rdbms.

No Portal involved

we are implementing some scenarios using custom webdynpro.in order to give one simple functionality to some (remote) users without give them sapgui.

When we start the webdynpro from abap, browser asks for a basic Authentication.

We do not want to use x.509 certificates

Is there no way to transfer logon credential from abap to webdynpro ?

The only way is to use Netweaver Single Sign On or third party solutions ?

Thanks

Mauro