Conditional formatting for Stacked Bar Chart

Dear All,

I'm in a bit of a dillema here, would be great to have your help;

I have a dataset which looks like this (a .xls file is also attached):

Researcher - Rec. Ppt - Start - Duration - Type of Researcherer
1 IHEID 4 21 ESR
2 ULB 12 22 ER
3 UW 17 19 ESR

I'm working with a stacked bar chart (making a Gantt chart through it). I want two different colors for the "Type of Researcher"; Red for ESR, and Blue for ER. The problem i'm facing is that i can't make the legend to show that. Whenever i try doing that my actual chart starts to change. The way i do is Right-Click on chart>Source Data>Series, but it doesn't work somehow. I just want my legend to have ESR and ER, with the colors red and blue in their respective boxes.

Any kind of suggestion/advice would be much appreciated.

Cheers!

PS: The .xls data file is attached.