Subdomain beginning with number no longer possible?

[ah-blabla]

I'm having a problem with cpanel, which won't let me add a sudomain beginning with a number, i.e. I'm trying to add the sudomain "6ra" to my domain, but cpanel claims:
"That is not a valid subdomain."
I'd already made exactly the subdomain last year, but then removed it again. It worked fine then, showing that it is a valid subdomain, however CPanel's latest version claims that it isn't. (It claims that any sudomain beginning with a number is not valid...)

Adding the same sudomain as an addon domain, i.e. filling in the complete address works fine though, so the problem lies somewhere in the subdomain addition code.

[rikichi8]

subdomain can only use the characters a-z can not use numbers

[ah-blabla]

subdomain can only use the characters a-z can not use numbers

1. I previously had exactly the same subdomain, beginning with the same number.
2. I was able to add the same subdomain as an addon domain, i.e. filling in the full adress, however cannot add it through the subdomain entry, even though I want it added as a simple subdomain. Since it's added as an addon domain though it uses up an extra ftp account, doesn't appear in the correct place, etc.
3. Subdomains can use numbers, even now I can use a number, cpanel only complains if the number is at the beginning of the subdomain, despite it having worked before, and adding the subdomain as an "additional domain" works.

[calistoy]

About when was the last time you were able to do that?

[ah-blabla]

About when was the last time you were able to do that?

Must have been October/November 2009.

[descalzo]

I just created subdomains '1201' and '6ra' on my account on Chopin.

[ah-blabla]

I just created subdomains '1201' and '6ra' on my account on Chopin.

It seems to be a problem specific to the cpanel installed on starka then, since it still won't let me create any subdomain beginning with a number. (It both says "That is not a valid subdomain." on the right hand side of the entry for a new subdomain, and complains about the same if I try to press the create button.)
Edit:
The problem actually lies with the javascript "validation": by disabling javascript I was able to input the subdomain and save it without complaints.