I recently got myself a Samsung Galaxy Trend Plus mobile phone.
I also bought a 32Gb microSD card with a view to storing some sound files. However, on connecting the device to my laptop I discovered that though I could see and read files on the SD card, I was unable to transfer files onto it. The only way to load files to the SD card was to physically remove the card and plug it into the laptop using a card adaptor, which was messy and tedious.
There is a solution however, and that is to install gMTP.
First run the following -
sudo apt-get install libmtp-common libmtp-dev libmtp-runtime libmtp9 mtp-tools gmtp python-pymtp
Then this -
sudo apt-get install libusb-dev
You should now see gMTP available on the main Menu (under All Applications).
Connect the phone and run the programme. Click "Connect". In the event it says that no RAW devices are found, just wait a few seconds for it to detect the phone.
Once connected you will be presented with an drop-down option of connecting to the phone or the card.
Files can now be transferred as normal.