some things you might have missed and I will try and list them.
1) Complete at least one lure of the wildcat quest in any nation: Bastok, Sandy, Windy and Jeuno then travel to whitegate and talk to Naja of Saleem Sentinals.
(The more nations you complete lure of the wildcat in, the more Naja pays you in imperial currancy and you can teleport from those nations to whitegate too.)
2) Unlock at least 1 runic portal by taking supplies to an immortal before entering a portal and then talking to Naja to become Private Second Class or PSC for short.
(Talk to the blue mage more then once at the outpost to be sure he has got the supplies from you or you will have to do it all again if you forget and enter the runic portal.)
At this point your mog locker will be available to use and you start off with 30 slots.
You can talk to Fubruhn outside the moghouse to change your settings for your locker.
Most people I know set it so you can access your locker from anywhere in the world but the lease costs more.
If you traded a stack of 99 bronze pieces and traded it to your moogle today, you will have paid for your locker acces till October 2014 which isn't bad for 30k from the AH.
Either that or wait for besieged to come and farm ISP to buy your coins.
I just did all of the above today and managed to solve my problem why I couldn't access my locker. Good luck with yours.
Lu Shangs Fishing Rod obtained: Feb 2005
Maat's cap Obtained: Saturday 31st July 2010
Ebisu Fishing Rod Obtained: Sunday 8th August 2010