Q: vector map patching

[Markus Neteler]

Hi,

currently I have the problem to merge a small vector map
in good digitizing quality and a second in less quality. 
The small one is part of the second - I want to *replace* 
a part of the map with less quality by overlaying this 
small map:

------------- 
|less qual. |
|           |
|           |
|  |----|   |
|  |good|   |
|  |qual|   |
-------------

How to perform such replacement in GRASS? I feel that v.patch
will just overlay both maps.

Thanks for assistance

   Markus