SEO Pro does not work right as a package dependecy

[DESIGNfromWITHIN]

I want to add this in my package, but this does not work, the download button does nothing in the dependencies tab.

$attr = array(
    'license' => file_get_contents($sources['docs'] . 'license.txt'),
    'readme' => file_get_contents($sources['docs'] . 'readme.txt'),
    'changelog' => file_get_contents($sources['docs'] . 'changelog.txt'),
    'requires' => array(
        'ace' => '>=1.6.4',
        'formit' => '>=2.2.8',
        'migx' => '>=2.9.6',
        'pdotools' => '>=2.1.20',
        'pthumb' => '>=2.3.3',
        'xrouting' => '>=1.4.1',
        'seopro' => '>=1.0.4'
    ),
);

This does not work either.

'SEO Pro' => '>=1.0.4',

Is the name SEOPro? SEO Pro or something else?
What sould I add to add SEO Pro as a dependecy?

[joeke]

@gpsietzema @DESIGNfromWITHIN Some time ago I've dug into the same problem for SEOTab (see Sterc/SEOTab#55). At the time it was a modx.com extras repo issue, but I'm not sure that is still the case, will investigate it again now.