How to use preset_mode from lame.h?

Question

I want to use presets from lame.h but don't know which function to use with preset_mode constants?

Constants:

/*presets*/
typedef enum preset_mode_e {
    /*values from 8 to 320 should be reserved for abr bitrates*/
    /*for abr I'd suggest to directly use the targeted bitrate as a value*/
    ABR_8 = 8,
    ABR_320 = 320,
    V9 = 410, /*Vx to match Lame and VBR_xx to match FhG*/
    VBR_10 = 410,
    V8 = 420,
    VBR_20 = 420,
    V7 = 430,
    VBR_30 = 430,
    V6 = 440,
    VBR_40 = 440,
    V5 = 450,
    VBR_50 = 450,
    V4 = 460,
    VBR_60 = 460,
    V3 = 470,
    VBR_70 = 470,
    V2 = 480,
    VBR_80 = 480,
    V1 = 490,
    VBR_90 = 490,
    V0 = 500,
    VBR_100 = 500,
    /*still there for compatibility*/
    R3MIX = 1000,
    STANDARD = 1001,
    EXTREME = 1002,
    INSANE = 1003,
    STANDARD_FAST = 1004,
    EXTREME_FAST = 1005,
    MEDIUM = 1006,
    MEDIUM_FAST = 1007
} preset_mode;

My assumption was to try lame_set_VBR_q or lame_set_VBR_quality, but it's really confusing. Is there any example available?

Big thanks in advance.