Zeta SH-09D - unlock problem

[grubas1]

Hello,
I recently bought Aquos SH-09D phone, and it is locked to NTT Docomo.
I go to my local gsm store, and they give me a test micro sim card and generate unlock code for this phone.

When they want to put unlock code, it is not possible because unlock code have small and big letters (1Zx, for example), and they can't give small latters, only big.

So I don't know what should do now? Thanks for any help.

I found on internet this guide,

Switch on SHARP SH-09D Aquos,
Type sequence *#*#4669#*#*
Select option 1 in menu
Enter the unlock code
The phone will reboot - enter original sim card
The phone is now unlocked.