Lemandarangequatelo,
you know, I was able to send the seeds eventually, my friend.
citrange,
here is the story: I was sending seeds for two years or so with no issues... until the last fall. When I brought small packages for England, Sweden, and Russia, a post office clerk told me (after 30 minutes of typing on her computer) that these countries do not allow import of any plant parts including seeds and she could not accept them. I went to another post office where I was told the same thing. They said that this regulation was new. I ended up coming back to the post office during their rush hour with the same packages but saying "gift" in the forms. The clerk was too busy to ask me about details.
Saying this, I am very sorry about braking the rules! However, feeling about them the same way Millet does, knowing that the seeds I was sending (that were virus-free to the best of my knowledge) will not end up in Spain or in any other citrus regions, and, most importantly, making a certain promise to my friends, I did not hesitate much to not disclose the content...
Of course, it is possible that usps clerks were somehow misinformed but this is what they were saying - my two cents.