With this simple setup where the cloud storage is used with an ME Storage Bus, none of the available items will show up in the AE2 system. A similar issues happens with Tom's Storage where only the first 27 slots will be shown there.

Relevant Tom's storage issue:
tom5454/Toms-Storage#445

I've found that a workaround is to break and replace your static cloud chest, this correctly updates the amount of available storage.

It seems unloading and reloading the chunk may also trigger the update.