You can configure firefighter to be role-based rather than user-based. Here, rather than getting a new userid when you use firefighter, the relevant roles are temporarily added to your own user. Then you should be able to run dynpros as your own user and have firefighter access when necessary.
You'll find info about this in the installation guide, and there are plenty of discussions here on SCN about it - just search for "role based firefighter". As far as I know, most people use a user-based, not role-based, firefighter configuration.
Steve.