Applying Service Packs to Netweaver 7.3 without solution manager

Hi,

I have installed Netweaver 7.3 and deployed a client application(for demo purposes) which all works fine.

However i now need to install the service packs so i can deploy the latest changes, such as long field names (16 to 30 chars) etc.

Documentation says in order to do this i need Solution Manager in order to build the stack.xml.

This seems a massive overhead, having painstaking built one system, i now need to build another one JUST to update the original one. It appears i also need solution manager if i wanted to upgrade Netweaver 7.4.

Is there a way to manually construct the stack.xml?

If i do need Solution Manager, can this be deployed on the same system or is new hardware required?

Any help, much appreciated.

Thanks

Jason