Error installing eggs with packages for different python version with virtualenv

I'm not able to install packages with a virtualenv set to a different python version. Here's my开发者_运维百科 $:

$ sudo apt-get install python-setuptools python-dev build-essential
$ sudo easy_install -U pip
$ sudo virtualenv  --no-site-packages --distribute --python=/usr/bin/python2.6 pootle
$ cd pootle
$ sudo pip install mysql-python

Among others, here the error:

 pymemcompat.h:10:20: fatal error: Python.h: File o directory non esistente

No problems, actually, using the default version of python installed on my system (2.7)ubuntu

$ sudo apt-get install python2.6-dev