Trouble configuring MarketPress store settings direct from database

While I am incredibly pleased with MarketPress, I am having trouble when attempting to configure the store settings directly from my WordPress SQL database. I connect successfully to my WordPress database and replace the 'mp_settings' option data with a string I am certain is valid, yet when reloading any page on my WordPress site, either in the admin section or a normal public page, the settings are reset to their default. I first thought this was because the string I was specifying was not valid, but I have also tried generating the settings I want via the WordPress admin page and then I have simply re-entered the string into the datbase, this too causes the settings to reset meaning that cannot be the issue.

I understand you may advise the configuration of MarketPress via the WordPress admin area, however, I would be very grateful if you could help me in configuring it directly from the database as I require configuration on multiple sites and, by no fault of yours, it would not be practical to configure the plugin in the usual way on every site.

Any help would be greatly appreciated.

Thank you.